Hong Kong's Law Society and Bar Association on Thursday condemned abusive graffiti sprayed by protesters on a court building that insulted a judge by name.

The groups called that “an affront to the rule of law and judicial integrity" in the former British colony, which has retained its unique judicial system free from the corruption and political interference so common on mainland China.

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A worker cleans the iconic lion statue in front of the international HSBC Bank branch that was painted with red paint in Hong Kong, Thursday, Jan. 2, 2020. A huge crowd gathered in Hong Kong Wednesday for an annual New Year's Day protest march as the months long pro-democracy movement extends into 2020. (AP PhotoVincent Yu)

Hong Kong's Law Society and Bar Association on Thursday condemned abusive graffiti sprayed by protesters on a court building that insulted a judge by name.

Students walks next to the iconic lion statue in front of the international HSBC Bank branch that was painted with red paint in Hong Kong, Thursday, Jan. 2, 2020. A huge crowd gathered in Hong Kong Wednesday for an annual New Year's Day protest march as the months long pro-democracy movement extends into 2020. (AP PhotoVincent Yu)

The incident came Wednesday during a New Year's Day anti-government march that swiftly devolved into running battles between police and hard-core demonstrators.

A man reads a newspaper reporting New Year's Day protest with the headline "Hong Kongers, Fight!" in Hong Kong, Thursday, Jan. 2, 2020. Hundreds of thousands of people packed Hong Kong streets for an annual New Year's Day protest on Wednesday as the monthslong pro-democracy movement extended into 2020 with further violence between police and demonstrators. (AP PhotoLee Jin-man)

Many protesters are driven concerns that China is gradually tightening its control over Hong Kong's institutions, from major businesses, to law enforcement and the media.

Protesters hold up banners during a rally in Hong Kong Thursday, Jan. 2, 2020. Hundreds of thousands of people packed Hong Kong streets for an annual New Year's Day protest on Wednesday as the monthslong pro-democracy movement extended into 2020 with further violence between police and demonstrators. The banner at left reads "Against authoritarianism, we are not afraid because we have each other." (AP PhotoLee Jin-man)

Kwok said police had arrested 420 people during the New Year holiday, bring the total arrested during the protests to around 7,000.

Protesters hold up their hands to represent their five demands during a rally in Hong Kong Thursday, Jan. 2, 2020. Hundreds of thousands of people packed Hong Kong streets for an annual New Year's Day protest on Wednesday as the monthslong pro-democracy movement extended into 2020 with further violence between police and demonstrators. The banner in the center reads: ""No rioters, only authoritarian government." (AP PhotoLee Jin-man)

Protesters hold up their hands to represent their five demands during a rally in Hong Kong Thursday, Jan. 2, 2020. Hundreds of thousands of people packed Hong Kong streets for an annual New Year's Day protest on Wednesday as the monthslong pro-democracy movement extended into 2020 with further violence between police and demonstrators. The banner in the center reads: ""No rioters, only authoritarian government." (AP PhotoLee Jin-man)

Residents watch from a tram as protesters rally in Hong Kong  Thursday, Jan. 2, 2020. Hundreds of thousands of people packed Hong Kong streets for an annual New Year's Day protest on Wednesday as the monthslong pro-democracy movement extended into 2020 with further violence between police and demonstrators. (AP PhotoLee Jin-man)

Residents watch from a tram as protesters rally in Hong Kong Thursday, Jan. 2, 2020. Hundreds of thousands of people packed Hong Kong streets for an annual New Year's Day protest on Wednesday as the monthslong pro-democracy movement extended into 2020 with further violence between police and demonstrators. (AP PhotoLee Jin-man)

A protester lays out placards in Hong Kong Thursday, Jan. 2, 2020. Hundreds of thousands of people packed Hong Kong streets for an annual New Year's Day protest on Wednesday as the monthslong pro-democracy movement extended into 2020 with further violence between police and demonstrators. (AP PhotoLee Jin-man)

A protester lays out placards in Hong Kong Thursday, Jan. 2, 2020. Hundreds of thousands of people packed Hong Kong streets for an annual New Year's Day protest on Wednesday as the monthslong pro-democracy movement extended into 2020 with further violence between police and demonstrators. (AP PhotoLee Jin-man)

Protesters hold up placards during a rally in Hong Kong  Thursday, Jan. 2, 2020. Hundreds of thousands of people packed Hong Kong streets for an annual New Year's Day protest on Wednesday as the monthslong pro-democracy movement extended into 2020 with further violence between police and demonstrators. (AP PhotoLee Jin-man)

Protesters hold up placards during a rally in Hong Kong Thursday, Jan. 2, 2020. Hundreds of thousands of people packed Hong Kong streets for an annual New Year's Day protest on Wednesday as the monthslong pro-democracy movement extended into 2020 with further violence between police and demonstrators. (AP PhotoLee Jin-man)

A worker cleans the iconic lion statue in front of the international HSBC Bank branch that was painted with red paint in Hong Kong, Thursday, Jan. 2, 2020. A huge crowd gathered in Hong Kong Wednesday for an annual New Year's Day protest march as the months long pro-democracy movement extends into 2020. (AP PhotoVincent Yu)

A worker cleans the iconic lion statue in front of the international HSBC Bank branch that was painted with red paint in Hong Kong, Thursday, Jan. 2, 2020. A huge crowd gathered in Hong Kong Wednesday for an annual New Year's Day protest march as the months long pro-democracy movement extends into 2020. (AP PhotoVincent Yu)

The incident came Wednesday during a New Year's Day anti-government march that swiftly devolved into running battles between police and hard-core demonstrators.

“The graffiti are outrageous and firmly condemned,”the joint letter stated. “Abusive comments implying that judicial decisions were made or influenced by political considerations are wholly unjustified."

Along with many civic and business groups, the Law Society and Bar Association had been critical of proposed extradition legislation that set off the original protests in June. They have been less outspoken about the increasingly violent protests except when the city's independent judiciary has been attacked.

Students walks next to the iconic lion statue in front of the international HSBC Bank branch that was painted with red paint in Hong Kong, Thursday, Jan. 2, 2020. A huge crowd gathered in Hong Kong Wednesday for an annual New Year's Day protest march as the months long pro-democracy movement extends into 2020. (AP PhotoVincent Yu)

Students walks next to the iconic lion statue in front of the international HSBC Bank branch that was painted with red paint in Hong Kong, Thursday, Jan. 2, 2020. A huge crowd gathered in Hong Kong Wednesday for an annual New Year's Day protest march as the months long pro-democracy movement extends into 2020. (AP PhotoVincent Yu)

Many protesters are driven concerns that China is gradually tightening its control over Hong Kong's institutions, from major businesses, to law enforcement and the media.

The attack on the court building was also condemned by police spokesman Kwok Ka-chuen at a briefing Thursday.

“In one of the most alarming cases, rioters spray-painted offensive words on the outer wall of the High Court to insult a judge," Kwok told reporters. “This kind of attack will make a dent in the spirit of the law and threaten the independence of the judiciary."

A man reads a newspaper reporting New Year's Day protest with the headline "Hong Kongers, Fight!" in Hong Kong, Thursday, Jan. 2, 2020. Hundreds of thousands of people packed Hong Kong streets for an annual New Year's Day protest on Wednesday as the monthslong pro-democracy movement extended into 2020 with further violence between police and demonstrators. (AP PhotoLee Jin-man)

A man reads a newspaper reporting New Year's Day protest with the headline "Hong Kongers, Fight!" in Hong Kong, Thursday, Jan. 2, 2020. Hundreds of thousands of people packed Hong Kong streets for an annual New Year's Day protest on Wednesday as the monthslong pro-democracy movement extended into 2020 with further violence between police and demonstrators. (AP PhotoLee Jin-man)

Kwok said police had arrested 420 people during the New Year holiday, bring the total arrested during the protests to around 7,000.

He said charges included illegal assembly, possession of offensive weapons and disorderly conduct in a public place. “Protester violence has reached a really critical level,” Kwok said. “For more than seven months, Hong Kong people have been living under the shadow of violent protests which have extended to almost every neighborhood of the city.”

Protesters hold up banners during a rally in Hong Kong Thursday, Jan. 2, 2020. Hundreds of thousands of people packed Hong Kong streets for an annual New Year's Day protest on Wednesday as the monthslong pro-democracy movement extended into 2020 with further violence between police and demonstrators. The banner at left reads "Against authoritarianism, we are not afraid because we have each other." (AP PhotoLee Jin-man)

Protesters hold up banners during a rally in Hong Kong Thursday, Jan. 2, 2020. Hundreds of thousands of people packed Hong Kong streets for an annual New Year's Day protest on Wednesday as the monthslong pro-democracy movement extended into 2020 with further violence between police and demonstrators. The banner at left reads "Against authoritarianism, we are not afraid because we have each other." (AP PhotoLee Jin-man)

Protesters hold up their hands to represent their five demands during a rally in Hong Kong Thursday, Jan. 2, 2020. Hundreds of thousands of people packed Hong Kong streets for an annual New Year's Day protest on Wednesday as the monthslong pro-democracy movement extended into 2020 with further violence between police and demonstrators. The banner in the center reads: ""No rioters, only authoritarian government." (AP PhotoLee Jin-man)

Protesters hold up their hands to represent their five demands during a rally in Hong Kong Thursday, Jan. 2, 2020. Hundreds of thousands of people packed Hong Kong streets for an annual New Year's Day protest on Wednesday as the monthslong pro-democracy movement extended into 2020 with further violence between police and demonstrators. The banner in the center reads: ""No rioters, only authoritarian government." (AP PhotoLee Jin-man)

Residents watch from a tram as protesters rally in Hong Kong  Thursday, Jan. 2, 2020. Hundreds of thousands of people packed Hong Kong streets for an annual New Year's Day protest on Wednesday as the monthslong pro-democracy movement extended into 2020 with further violence between police and demonstrators. (AP PhotoLee Jin-man)

Residents watch from a tram as protesters rally in Hong Kong Thursday, Jan. 2, 2020. Hundreds of thousands of people packed Hong Kong streets for an annual New Year's Day protest on Wednesday as the monthslong pro-democracy movement extended into 2020 with further violence between police and demonstrators. (AP PhotoLee Jin-man)

A protester lays out placards in Hong Kong Thursday, Jan. 2, 2020. Hundreds of thousands of people packed Hong Kong streets for an annual New Year's Day protest on Wednesday as the monthslong pro-democracy movement extended into 2020 with further violence between police and demonstrators. (AP PhotoLee Jin-man)

A protester lays out placards in Hong Kong Thursday, Jan. 2, 2020. Hundreds of thousands of people packed Hong Kong streets for an annual New Year's Day protest on Wednesday as the monthslong pro-democracy movement extended into 2020 with further violence between police and demonstrators. (AP PhotoLee Jin-man)

Protesters hold up placards during a rally in Hong Kong  Thursday, Jan. 2, 2020. Hundreds of thousands of people packed Hong Kong streets for an annual New Year's Day protest on Wednesday as the monthslong pro-democracy movement extended into 2020 with further violence between police and demonstrators. (AP PhotoLee Jin-man)

Protesters hold up placards during a rally in Hong Kong Thursday, Jan. 2, 2020. Hundreds of thousands of people packed Hong Kong streets for an annual New Year's Day protest on Wednesday as the monthslong pro-democracy movement extended into 2020 with further violence between police and demonstrators. (AP PhotoLee Jin-man)