Riot police have blocked hundreds of doctors and nurses from marching to Venezuela's presidential palace to protest low pay and shortages of medical supplies amid the nation's deepening crisis.

Thursday's demonstration in Caracas was the first attempt by protesters to reach the presidential palace since massive anti-government protests last year.

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A nurse offers a paper flower to a police officer during a protest against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. The nurses were confronted by a phalanx of police officers that prevented them from marching towards Miraflores Presidential Palace several miles away. (AP PhotoFernando Llano)

Riot police have blocked hundreds of doctors and nurses from marching to Venezuela's presidential palace to protest low pay and shortages of medical supplies amid the nation's deepening crisis.

Nurse Monica Arangure, center, wears a crown and a band that in Spanish says "My needs" during a protest demanding higher, fair wages and against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. The nurses were confronted by a phalanx of police officers that prevented them from marching towards Miraflores Presidential Palace several miles away. (AP PhotoAriana Cubillos)

The once-wealthy oil-producing nation is in crisis economically and politically after two decades of socialist rule.

A woman wears a cardboard hat with dry grass on top and letters in Spanish that read "CLAP", meaning the boxes with food provided by the government run "CLAP" program which stands for Local Committees of Supply and Production, during a protests against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. (AP PhotoAriana Cubillos)

The protest ended without violence.

One hundred Bolivar bills lay on the ground close to the boots of several police officers, after they were thrown by protesters during a protest against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. The government is lopping off five zeroes from the "Strong Bolivar," which will remain legal tender, in a bid to tame inflation the IMF estimates will reach 1,000,000 percent this year. (AP PhotoAriana Cubillos)

One hundred Bolivar bills lay on the ground close to the boots of several police officers, after they were thrown by protesters during a protest against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. The government is lopping off five zeroes from the "Strong Bolivar," which will remain legal tender, in a bid to tame inflation the IMF estimates will reach 1,000,000 percent this year. (AP PhotoAriana Cubillos)

A line of police officers stand blocking a street, stoping a protests against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. Protesting nurses were confronted by the phalanx of police officers that prevented them from marching towards Miraflores Presidential Palace several miles away. (AP PhotoAriana Cubillos)

A line of police officers stand blocking a street, stoping a protests against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. Protesting nurses were confronted by the phalanx of police officers that prevented them from marching towards Miraflores Presidential Palace several miles away. (AP PhotoAriana Cubillos)

A demonstrator shows a bank note of five hundred Bolivars to a line of police officers during protest in Caracas, Venezuela, Thursday, Aug. 16, 2018. If multiple exchange rates and cash shortages driven by hyperinflation weren't causing enough financial havoc for Venezuelans, starting Monday there will be two official currencies in circulation as the socialist government begins rolling out the new "Sovereign Bolivar." (AP PhotoFernando Llano)

A demonstrator shows a bank note of five hundred Bolivars to a line of police officers during protest in Caracas, Venezuela, Thursday, Aug. 16, 2018. If multiple exchange rates and cash shortages driven by hyperinflation weren't causing enough financial havoc for Venezuelans, starting Monday there will be two official currencies in circulation as the socialist government begins rolling out the new "Sovereign Bolivar." (AP PhotoFernando Llano)

Nurses holds a sign with a fake Venezuelan's bills, representing how low their salaries have been devalued by inflation, during a protests against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. The government is lopping off five zeroes from the "Strong Bolivar," which will remain legal tender, in a bid to tame inflation the IMF estimates will reach 1,000,000 percent this year. But economists see it as a Band-Aid solution more likely to freeze up the payment system than address Venezuela's economic problems. (AP PhotoAriana Cubillos)

Nurses holds a sign with a fake Venezuelan's bills, representing how low their salaries have been devalued by inflation, during a protests against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. The government is lopping off five zeroes from the "Strong Bolivar," which will remain legal tender, in a bid to tame inflation the IMF estimates will reach 1,000,000 percent this year. But economists see it as a Band-Aid solution more likely to freeze up the payment system than address Venezuela's economic problems. (AP PhotoAriana Cubillos)

People lineup outside of a bank to get some cash in Caracas, Venezuela, Thursday, Aug. 16, 2018. If multiple exchange rates and cash shortages driven by hyperinflation weren't causing enough financial havoc for Venezuelans, starting Monday there will be two official currencies in circulation as the socialist government begins rolling out the new "Sovereign Bolivar." (AP PhotoFernando Llano)

People lineup outside of a bank to get some cash in Caracas, Venezuela, Thursday, Aug. 16, 2018. If multiple exchange rates and cash shortages driven by hyperinflation weren't causing enough financial havoc for Venezuelans, starting Monday there will be two official currencies in circulation as the socialist government begins rolling out the new "Sovereign Bolivar." (AP PhotoFernando Llano)

A nurse shouts anti-government slogans during a protests demanding higher, fair wages and against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. The nurses were confronted by a phalanx of police officers that prevented them from marching towards Miraflores Presidential Palace several miles away. (AP PhotoAriana Cubillos)

A nurse shouts anti-government slogans during a protests demanding higher, fair wages and against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. The nurses were confronted by a phalanx of police officers that prevented them from marching towards Miraflores Presidential Palace several miles away. (AP PhotoAriana Cubillos)

Nurses shout anti-government slogans during a protests demanding higher, fair wages and against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. The nurses were confronted by a phalanx of police officers that prevented them from marching towards Miraflores Presidential Palace several miles away. (AP PhotoAriana Cubillos)

Nurses shout anti-government slogans during a protests demanding higher, fair wages and against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. The nurses were confronted by a phalanx of police officers that prevented them from marching towards Miraflores Presidential Palace several miles away. (AP PhotoAriana Cubillos)

Venezuelan Bolivarian national police officers make a barrier to block a group of nurses and employees of public hospitals from marching towards Miraflores Presidential palace, during a protest against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. (AP PhotoFernando Llano)

Venezuelan Bolivarian national police officers make a barrier to block a group of nurses and employees of public hospitals from marching towards Miraflores Presidential palace, during a protest against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. (AP PhotoFernando Llano)

Nurses shout anti-government slogans during a protests demanding higher, fair wages and against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. The nurses were confronted by a phalanx of police officers that prevented them from marching towards Miraflores Presidential Palace several miles away. (AP PhotoAriana Cubillos)

Nurses shout anti-government slogans during a protests demanding higher, fair wages and against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. The nurses were confronted by a phalanx of police officers that prevented them from marching towards Miraflores Presidential Palace several miles away. (AP PhotoAriana Cubillos)

A nurse shouts anti-government slogans during a protests against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. The nurses were confronted by a phalanx of police officers that prevented them from marching towards Miraflores Presidential Palace several miles away. (AP PhotoAriana Cubillos)

A nurse shouts anti-government slogans during a protests against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. The nurses were confronted by a phalanx of police officers that prevented them from marching towards Miraflores Presidential Palace several miles away. (AP PhotoAriana Cubillos)

Nurses shout anti-government slogans as they are confronted by a line of police officers during a protests against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. The nurses were confronted by a phalanx of police officers that prevented them from marching towards Miraflores Presidential Palace several miles away. (AP PhotoAriana Cubillos)

Nurses shout anti-government slogans as they are confronted by a line of police officers during a protests against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. The nurses were confronted by a phalanx of police officers that prevented them from marching towards Miraflores Presidential Palace several miles away. (AP PhotoAriana Cubillos)

Nurses shout anti-government slogans outside a hospital during a protests against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. The nurses were confronted by a phalanx of police officers that prevented them from marching towards Miraflores Presidential Palace several miles away. (AP PhotoFernando Llano)

Nurses shout anti-government slogans outside a hospital during a protests against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. The nurses were confronted by a phalanx of police officers that prevented them from marching towards Miraflores Presidential Palace several miles away. (AP PhotoFernando Llano)

Nurses shout anti-government slogans outside a hospital during a protests against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. The nurses were confronted by a phalanx of police officers that prevented them from marching towards Miraflores Presidential Palace several miles away. (AP PhotoFernando Llano)

Nurses shout anti-government slogans outside a hospital during a protests against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. The nurses were confronted by a phalanx of police officers that prevented them from marching towards Miraflores Presidential Palace several miles away. (AP PhotoFernando Llano)

The medical professionals are demanding action by President Nicolas Maduro, who's overseeing a crisis marked by widespread shortages and mass migration from the country.

A nurse offers a paper flower to a police officer during a protest against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. The nurses were confronted by a phalanx of police officers that prevented them from marching towards Miraflores Presidential Palace several miles away. (AP PhotoFernando Llano)

A nurse offers a paper flower to a police officer during a protest against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. The nurses were confronted by a phalanx of police officers that prevented them from marching towards Miraflores Presidential Palace several miles away. (AP PhotoFernando Llano)

The once-wealthy oil-producing nation is in crisis economically and politically after two decades of socialist rule.

Rows of heavily armed riot police blocked roughly 400 medical professionals shortly after launching their march.

Ana Rosario Contreras of the Association of Illnesses says they're demanding the government provide basic supplies to treat patients.

Nurse Monica Arangure, center, wears a crown and a band that in Spanish says "My needs" during a protest demanding higher, fair wages and against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. The nurses were confronted by a phalanx of police officers that prevented them from marching towards Miraflores Presidential Palace several miles away. (AP PhotoAriana Cubillos)

Nurse Monica Arangure, center, wears a crown and a band that in Spanish says "My needs" during a protest demanding higher, fair wages and against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. The nurses were confronted by a phalanx of police officers that prevented them from marching towards Miraflores Presidential Palace several miles away. (AP PhotoAriana Cubillos)

The protest ended without violence.

A woman wears a cardboard hat with dry grass on top and letters in Spanish that read "CLAP", meaning the boxes with food provided by the government run "CLAP" program which stands for Local Committees of Supply and Production, during a protests against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. (AP PhotoAriana Cubillos)

A woman wears a cardboard hat with dry grass on top and letters in Spanish that read "CLAP", meaning the boxes with food provided by the government run "CLAP" program which stands for Local Committees of Supply and Production, during a protests against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. (AP PhotoAriana Cubillos)

One hundred Bolivar bills lay on the ground close to the boots of several police officers, after they were thrown by protesters during a protest against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. The government is lopping off five zeroes from the "Strong Bolivar," which will remain legal tender, in a bid to tame inflation the IMF estimates will reach 1,000,000 percent this year. (AP PhotoAriana Cubillos)

One hundred Bolivar bills lay on the ground close to the boots of several police officers, after they were thrown by protesters during a protest against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. The government is lopping off five zeroes from the "Strong Bolivar," which will remain legal tender, in a bid to tame inflation the IMF estimates will reach 1,000,000 percent this year. (AP PhotoAriana Cubillos)

A line of police officers stand blocking a street, stoping a protests against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. Protesting nurses were confronted by the phalanx of police officers that prevented them from marching towards Miraflores Presidential Palace several miles away. (AP PhotoAriana Cubillos)

A line of police officers stand blocking a street, stoping a protests against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. Protesting nurses were confronted by the phalanx of police officers that prevented them from marching towards Miraflores Presidential Palace several miles away. (AP PhotoAriana Cubillos)

A demonstrator shows a bank note of five hundred Bolivars to a line of police officers during protest in Caracas, Venezuela, Thursday, Aug. 16, 2018. If multiple exchange rates and cash shortages driven by hyperinflation weren't causing enough financial havoc for Venezuelans, starting Monday there will be two official currencies in circulation as the socialist government begins rolling out the new "Sovereign Bolivar." (AP PhotoFernando Llano)

A demonstrator shows a bank note of five hundred Bolivars to a line of police officers during protest in Caracas, Venezuela, Thursday, Aug. 16, 2018. If multiple exchange rates and cash shortages driven by hyperinflation weren't causing enough financial havoc for Venezuelans, starting Monday there will be two official currencies in circulation as the socialist government begins rolling out the new "Sovereign Bolivar." (AP PhotoFernando Llano)

Nurses holds a sign with a fake Venezuelan's bills, representing how low their salaries have been devalued by inflation, during a protests against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. The government is lopping off five zeroes from the "Strong Bolivar," which will remain legal tender, in a bid to tame inflation the IMF estimates will reach 1,000,000 percent this year. But economists see it as a Band-Aid solution more likely to freeze up the payment system than address Venezuela's economic problems. (AP PhotoAriana Cubillos)

Nurses holds a sign with a fake Venezuelan's bills, representing how low their salaries have been devalued by inflation, during a protests against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. The government is lopping off five zeroes from the "Strong Bolivar," which will remain legal tender, in a bid to tame inflation the IMF estimates will reach 1,000,000 percent this year. But economists see it as a Band-Aid solution more likely to freeze up the payment system than address Venezuela's economic problems. (AP PhotoAriana Cubillos)

People lineup outside of a bank to get some cash in Caracas, Venezuela, Thursday, Aug. 16, 2018. If multiple exchange rates and cash shortages driven by hyperinflation weren't causing enough financial havoc for Venezuelans, starting Monday there will be two official currencies in circulation as the socialist government begins rolling out the new "Sovereign Bolivar." (AP PhotoFernando Llano)

People lineup outside of a bank to get some cash in Caracas, Venezuela, Thursday, Aug. 16, 2018. If multiple exchange rates and cash shortages driven by hyperinflation weren't causing enough financial havoc for Venezuelans, starting Monday there will be two official currencies in circulation as the socialist government begins rolling out the new "Sovereign Bolivar." (AP PhotoFernando Llano)

A nurse shouts anti-government slogans during a protests demanding higher, fair wages and against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. The nurses were confronted by a phalanx of police officers that prevented them from marching towards Miraflores Presidential Palace several miles away. (AP PhotoAriana Cubillos)

A nurse shouts anti-government slogans during a protests demanding higher, fair wages and against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. The nurses were confronted by a phalanx of police officers that prevented them from marching towards Miraflores Presidential Palace several miles away. (AP PhotoAriana Cubillos)

Nurses shout anti-government slogans during a protests demanding higher, fair wages and against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. The nurses were confronted by a phalanx of police officers that prevented them from marching towards Miraflores Presidential Palace several miles away. (AP PhotoAriana Cubillos)

Nurses shout anti-government slogans during a protests demanding higher, fair wages and against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. The nurses were confronted by a phalanx of police officers that prevented them from marching towards Miraflores Presidential Palace several miles away. (AP PhotoAriana Cubillos)

Venezuelan Bolivarian national police officers make a barrier to block a group of nurses and employees of public hospitals from marching towards Miraflores Presidential palace, during a protest against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. (AP PhotoFernando Llano)

Venezuelan Bolivarian national police officers make a barrier to block a group of nurses and employees of public hospitals from marching towards Miraflores Presidential palace, during a protest against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. (AP PhotoFernando Llano)

Nurses shout anti-government slogans during a protests demanding higher, fair wages and against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. The nurses were confronted by a phalanx of police officers that prevented them from marching towards Miraflores Presidential Palace several miles away. (AP PhotoAriana Cubillos)

Nurses shout anti-government slogans during a protests demanding higher, fair wages and against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. The nurses were confronted by a phalanx of police officers that prevented them from marching towards Miraflores Presidential Palace several miles away. (AP PhotoAriana Cubillos)

A nurse shouts anti-government slogans during a protests against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. The nurses were confronted by a phalanx of police officers that prevented them from marching towards Miraflores Presidential Palace several miles away. (AP PhotoAriana Cubillos)

A nurse shouts anti-government slogans during a protests against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. The nurses were confronted by a phalanx of police officers that prevented them from marching towards Miraflores Presidential Palace several miles away. (AP PhotoAriana Cubillos)

Nurses shout anti-government slogans as they are confronted by a line of police officers during a protests against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. The nurses were confronted by a phalanx of police officers that prevented them from marching towards Miraflores Presidential Palace several miles away. (AP PhotoAriana Cubillos)

Nurses shout anti-government slogans as they are confronted by a line of police officers during a protests against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. The nurses were confronted by a phalanx of police officers that prevented them from marching towards Miraflores Presidential Palace several miles away. (AP PhotoAriana Cubillos)

Nurses shout anti-government slogans outside a hospital during a protests against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. The nurses were confronted by a phalanx of police officers that prevented them from marching towards Miraflores Presidential Palace several miles away. (AP PhotoFernando Llano)

Nurses shout anti-government slogans outside a hospital during a protests against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. The nurses were confronted by a phalanx of police officers that prevented them from marching towards Miraflores Presidential Palace several miles away. (AP PhotoFernando Llano)

Nurses shout anti-government slogans outside a hospital during a protests against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. The nurses were confronted by a phalanx of police officers that prevented them from marching towards Miraflores Presidential Palace several miles away. (AP PhotoFernando Llano)

Nurses shout anti-government slogans outside a hospital during a protests against the government of President Nicolas Maduro, in Caracas, Venezuela, Thursday, Aug. 16, 2018. The nurses were confronted by a phalanx of police officers that prevented them from marching towards Miraflores Presidential Palace several miles away. (AP PhotoFernando Llano)