A fire in the Sian Ka'an nature reserve on Mexico's Yucatan Peninsula has spread to more than 6,000 acres (2,500 hectares) and local authorities say it's 30 percent under control.

The Quintana Roo Environment Department says the fire's advance across the brush and grasslands has slowed as of Monday.

Environment Secretary Afredo Arellano told Imagen Radio that drought and intense heat contributed to the fire.

This photo distributed by Mexico’s Secretary of Ecology and the Environment (SEMA) in Quintana Roo state shows a fire burning in the Sian Ka'an nature reserve on the Yucatan peninsula, near Felipe Carrillo Puerto, Mexico, Sunday, July 14, 2019. The civil protection coordinator for the state of Quintana Roo said Sunday the fire has already consumed 600 hectares (1,500 acres) of brush and other plants. (SEMA via AP)

This photo distributed by Mexico’s Secretary of Ecology and the Environment (SEMA) in Quintana Roo state shows a fire burning in the Sian Ka'an nature reserve on the Yucatan peninsula, near Felipe Carrillo Puerto, Mexico, Sunday, July 14, 2019. The civil protection coordinator for the state of Quintana Roo said Sunday the fire has already consumed 600 hectares (1,500 acres) of brush and other plants. (SEMA via AP)

More than 50 firefighters and a water-dropping Air Force helicopter are working to control the blaze.

The Sian Ka'an reserve on Mexico's Caribbean coast is a UNESCO World Heritage site and an important tourist destination. It includes jungle, wetlands and coral reef, as well as Mayan archaeological sites and pumas, monkeys and crocodiles.