Hong Kong's chief executive Carrie Lam condemned the "extreme use of violence" of protesters who stormed into a local government building on Monday, destroying pictures and daubing walls with graffiti in a direct challenge to China.
Lam, under fire for her handling of a controversial extradition bill, said "nothing is more important than the rule of law in Hong Kong" and said she hoped "society will return to normal as soon as possible".
Hong Kong police cleared hundreds of protesters who stormed the city's legislative council building on Monday, in an operation that followed protests marking the anniversary of the city's handover to Chinese rule.
Pictures showed people using tools to smash through the glass windows of the legislature building or breaking through shutters.
Protesters carried road signs, others corrugated iron sheets and pieces of scaffolding, as they barged into the council building. Some sat at legislators' desks, checking their phones, while others scrawled "anti-extradition" on chamber walls.
Ahead of a flag raising ceremony earlier in the day, police fired pepper spray to disperse demonstrators, who responded by raising their own Hong Kong flag and a black flag at half mast.
Other graffiti called for Hong Kong leader Carrie Lam to step down, while pictures of some lawmakers were defaced. "HK Is Not China" was painted in black on a white pillar.
The police arrived by bus and ran into position as about a thousand gathered around the Legislative Council building in the heart of the former British colony's financial district.
The government called for an immediate end to the violence, saying it had stopped all work on extradition bill amendments and that the legislation would automatically lapse in July next year.
There was no immediate response from the protesters, although some appeared to retreat as the evening wore on. Others were reinforcing their street barricades.
Monday marked the 22nd anniversary of China's takeover of the former British colony, which comes at a time of particular turmoil with the mainland.
More than a million people have taken part in protests in Hong Kong in the last three weeks against a proposed extradition bill that would see suspected criminals be taken to the mainland to face trial.
Activists argue that this process could be abused by the Beijing government in order to make its critics "disappear".
Hong Kong leader Carrie Lam, who has faced calls to step down, eventually suspended the bill but has not scrapped it.
Lam defended her handling of the bill at a press conference on Tuesday, saying "it is not true to say that the government has not responded" reiterating that there was no timetable or plan to resume the debate of the extradition bill.
She had appeared in public on Monday for the first time in two weeks and promised to do more to listen to public sentiment.
She said: "The incident that happened in recent months has led to controversies and disputes between the public and the government."
"After this incident, I will learn the lesson and ensure that the government’s future work will be closer and more responsive to the aspirations, sentiments and opinions of the community."
In a statement, British foreign secretary Jeremy Hunt emphasised the importance of upholding a "One Country, Two Systems" principle between China and the autonomous state.
"It is imperative that Hong Kong’s high degree of autonomy, and the rights and freedoms of the Hong Kong people, are fully respected in line with the Joint Declaration and the Hong Kong Basic Law," he said.
"We have made our position on this clear to the Chinese Government, both publicly and in private, and will continue to do so."