The resurgence of violence and vandalism on Sunday vindicates the urgent need for a national security law in the city, the Hong Kong government said as it condemned extensive street violence and open advocacy of Hong Kong independence during unlawful assemblies on the same day.

"The violent acts in Causeway Bay and Wan Chai today showed that advocates of Hong Kong independence and rioters remain rampant, reinforcing the need and urgency for the legislation on national security," the government said in a statement.

Violence erupted on Sunday at illegal rallies against the nation's top legislature's move to enact a national security law for the special administrative region. Anti-government protesters paralyzed Causeway Bay and Wan Chai on Hong Kong Island — two busy shopping districts. Groups of black-clad radical protesters clashed with police, vandalized shops and attacked people with different political views.

By 9.30 pm on Sunday, police had arrested more than 180 people for several offenses including unlawful assemblies and causing disorder in public places.

Using the same tactics as those employed during last year's social unrest, radical protesters set fires on streets, vandalized traffic lights and blocked major thoroughfares with debris in Wan Chai. The windows of some shops in Causeway Bay were smashed by rioters with bricks and rocks.

Residents holding different political opinions to the radicals, including a lawyer surnamed Chan, were attacked during the chaos. A video clip circulating on the internet shows the lawyer in a white T-shirt being assaulted by a gang of black-clad radicals in Causeway Bay.

The man is down on the ground while radicals kick and beat him with umbrellas. His head bleeds and his shirt is torn; the man then tries to get up and escape his assailants.

At these unlawful assemblies, some separatists also waved flags advocating Hong Kong independence.

The Hong Kong Special Administrative Region government denounced these acts by rioters and separatists, and voiced its support for the police.

These "outrageous" acts of violence and vandalism imposed serious threats to the city's public safety and the separatists' acts undermined Hong Kong's interests, a government's spokesman said in a statement.

The fundamental intention of the national security legislation in Hong Kong is to protect the nation's security and safeguard Hong Kong's stability and prosperity. It will therefore ensure Hong Kong residents' rights and freedoms are well-protected, the spokesman said.

Given that Hong Kong's economy has been seriously battered by months of social unrest last year, the government lamented the radicals' violent acts were "extremely irresponsible". They had hurt businesses and increased the risk of infection amid the coronavirus pandemic.

Hong Kong's economy has suffered greatly during the epidemic and cannot handle further unrest, the spokesman said.

The HKSAR government urged residents to draw a line with rioters and to condemn violence.

Police also condemned law-breakers, saying no civilized society would consider such unlawful behavior to be "protests". Police pledged to bring law-breakers to justice and urged the public to express their opinions in a peaceful, rational way.

Melissa Pang Kaye, president of the Law Society of Hong Kong (LSHK), also condemned the radicals' violent and illegal acts.

Pang said she was "grieving" and "furious" that a LSHK member was seriously injured after being attacked by black-clad rioters.

She noted that abiding by the law was one of fundamental aspects of the rule of law. Pang reiterated that illegal acts and violence could not be accepted — no matter the reason for it.

Pang believes lawyers should break their silence and speak out against violence.