Hong Kong police fired tear gas to try to disperse hundreds of protesters, some of whom stormed the legislature, destroyed pictures and daubed walls with graffiti, on the anniversary of the city's 1997 return to Chinese rule on Monday.

After the protesters had largely dispersed, it was announced that Hong Kong Leader Carrie Lam would meet with the press at 4 a.m. local time in police headquarters, according to the South China Morning Post.

Police arrived by bus and ran into position as about a thousand protesters gathered around the Legislative Council building in the heart of the former British colony's financial district.

Police fired several rounds of tear gas as protesters held up umbrellas to protect themselves or fled. Plumes of smoke billowed across major thoroughfares and in between some of the world's tallest skyscrapers.

Protesters had 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.

Other graffiti called for Lam to step down, while pictures of some lawmakers were defaced.

"HK Is Not China" was painted in black on a white pillar.

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.

A small group of mostly students wearing hard hats and masks had used a metal trolley, poles and scaffolding to charge again and again at the compound's reinforced glass doors, which eventually gave.

The Legislative Council Secretariat released a statement canceling business for Tuesday. The central government offices said they would close on Tuesday "owing to security consideration," while all guided tours to the Legislative Council complex were suspended until further notice.

Riot police in helmets and carrying batons earlier fired pepper spray as the standoff continued into the sweltering heat of the evening. Some demonstrators removed steel bars that were reinforcing parts of the council building.

Banners hanging over flyovers at the protest site read: "Free Hong Kong."

The protesters, some with cling film wrapped around their arms to protect them from tear gas, once again paralyzed parts of the Asian financial hub as they occupied roads after blocking them off with metal barriers.

Lam suspended the extradition bill on June 15 after some of the largest and most violent protests in the city in decades, but stopped short of protesters' demands to scrap it.

It was not immediately clear if the announcement that it would lapse would ease the tension.

The Beijing-backed leader is now clinging on to her job at a time of an unprecedented backlash against the government that poses the greatest popular challenge to Chinese leader Xi Jinping since he came to power in 2012.

"The kind of deafness that I see in the government this time around despite these protests is really worrying. The complete disregard for the will of the people is what alarms me," said Steve, a British lawyer who has worked in Hong Kong for 30 years.

"If this bill is not completely scrapped, I will have no choice but to leave my home, Hong Kong."

Opponents of the extradition bill, which would allow people to be sent to mainland China for trial in courts controlled by the Communist Party, fear it is a threat to Hong Kong's much-cherished rule of law.

Hong Kong returned to China under a "one country, two systems" formula that allows freedoms not enjoyed in mainland China, including freedom to protest and an independent judiciary.

Beijing denies interfering but, for many Hong Kong residents, the extradition bill is the latest step in a relentless march towards mainland control.

China has been angered by criticism from Western capitals, including Washington and London, about the legislation. Beijing said on Monday that Britain had no responsibility for Hong Kong any more and was opposed to its "gesticulating" about the territory.

The European Union on Monday called for restraint and dialog to find a way forward.