The Hong Kong Bar Association and the Law Society of Hong Kong issued statements condemning fires that were set at two courthouses Sunday night during a mass anti-government demonstration, with several current and former global law firm partners signing on to one of the statements.

On Monday, the Hong Kong Bar Association issued a rare, strongly worded statement saying that it "deplores in the strongest possible terms the acts of arson and vandalism at the Court of Final Appeal and High Court buildings".

Hundreds of thousands of people marched on Sunday in a mostly non-violent demonstration. But isolated violent acts did occur during the protest. They included one incident in which protesters set a fire outside a gate of the High Court and defaced the building's exterior walls, and another in which they started a fire at the entrance to the Court of Final Appeal, the highest court in Hong Kong, and vandalised the historic building, according to Radio Television Hong Kong (RTHK), the government-funded public broadcasting service in Hong Kong.

"People who commit such acts are not genuine protestors but criminals," the bar's statement read, using unusually harsh terms. "They must be brought to justice. Their acts cannot be defended or justified in any manner whatsoever, and were not committed in the exercise of any rights in a civilised society governed by the rule of law."

Also on Monday, the Law Society of Hong Kong, the city's professional body for solicitors, issued a similar statement condemning Sunday's courthouse fires.

"Venting dissatisfaction by throwing petrol bombs at court buildings and vandalising property must be abhorred. Those who committed these criminal acts must stop taking the law into their own hands," the Law Society said. "These acts will not help resolve any problem."

On Tuesday, the Law Society issued a second statement about the events, signed by 13 past presidents of the organisation.

"We strongly condemn anyone who attempts to put pressure on the courts through violence or other unlawful means," the statement said. "Hong Kong is a society ruled by law. Everyone must trust and respect the rule of law."

Several current and former partners at global firms signed on to this statement, including Huen Wong, a partner with Fried, Frank, Harris, Shriver & Jacobson; Dieter Yih, former head of Milbank's Hong Kong law practice; and Thomas So, a Mayer Brown partner and the immediate past president of the Law Society.

In November, the Hong Kong Bar condemned a fire set at a court building in Shatin, saying that the attack on the court building was "an attack on the independent judicial authority" of Hong Kong and one of the most corrosive to the rule of law.

The bar's November statement also stressed that it opposed all instances of violence and arson that "caused serious and extensive damage and even life-threatening personal injuries", and that "attacks on private property are bad enough". That statement came after the professional body for barristers in the city faced criticism for not publicly denouncing acts of violence committed by members of the protest movement.

In October, Edwin Choy, SC, resigned from his post as vice-chair of the Bar Council, the organisation's governing body. In an op-ed in the South China Morning Post, Choy, who has defended political dissidents, wrote that the Bar Council's silence on protester violence was the reason for his departure.