The city's police chief last night sought to defuse escalating tensions between the government and residents by issuing a clarification about accusations of rioting, hours after hundreds of protesters gathered outside Chief Executive Carrie Lam's office building to demand her exit.

Hong Kong Police Commissioner Stephen Lo clarified that his earlier comments on rioting applied only to "the behaviour displayed by some protesters" who threw bricks or metal poles at officers. "As such, those others who have participated in the same public order event but have not engaged in any violent acts need not worry about committing a rioting offence," he said, adding that the threshold for prosecution on a rioting charge "is very high".

Last Wednesday, Mr Lo had characterised the clashes that day between officers and protesters as rioting, which carries a 10-year jail term. So far, the authorities have arrested 15 individuals on suspicion of rioting or other violent offences. Of these, five are suspected to have been arrested for riot-related offences.

Mr Lo said police detained another 17 people last Wednesday for allegedly committing other crimes, including failure to produce identity documents, loitering and possession of equipment for illegal purposes.

His comments came hours after hundreds of protesters forced the closure of Lung Wo Road next to Mrs Lam's office building in Admiralty. Chanting "withdraw the Bill" and "(we want) dialogue", the protesters - mainly young, with some even in school uniforms - demanded the leader fully withdraw the controversial extradition Bill, step down and remove characterisation of last Wednesday's clashes as "rioting".

Activist Joshua Wong, who was released from prison yesterday morning, turned up in the afternoon at Tamar Park to rally protesters who cheered him.

"Unfortunately I couldn't join the rallies or demonstrations within the past few weeks, but now is the time for me to join this fight," he told the media in English. "It is time for us to urge Carrie Lam to withdraw the extradition law proposal, to take responsibility to step down and to face the two million people who have joined the fight and urged her to bear the political responsibilities."

Mr Wong, 22, was one of the leaders of the 2014 "Umbrella Movement" pro-democracy protests that blocked major roads in Hong Kong for 79 days. He was freed after serving a five-week jail term for contempt of court.

Calls for a general strike yesterday were not heeded, with a few reports of groups staging such activities.

Residents had mixed feelings about the protests.

Ms Simone Monteiro, 52, said she could not leave her house on Sunday due to the large crowds, but said she did not mind the inconvenience. "If they do this and they have good results, (achieve) what they want, it is okay, they can continue. But if they stay and see that they won't get what they want, they need to stop."

Madam Zhong Sin Kin, 68, thinks the young protesters are focusing on the "wrong things".

"It doesn't matter if they want to protest, but there cannot be disruptions to our daily lives, violence or bloodshed. I hope that in my lifetime I can see change, that Hong Kong can learn from Singapore. Eastern democracies are different from the West, and Western systems are not suitable for us."

A Hong Konger who declined to give his name said in Cantonese: "Old people like us don't appreciate this kind of behaviour. We don't like to see such situations."

Hundreds of thousands of people took to the streets over two consecutive weekends, prompting the government to suspend the extradition Bill, which would allow Hong Kong to send fugitives to the mainland for trials that critics said would not be fair. Protesters also fear the law could be used on political dissidents or activists.

On Sunday, organisers said nearly two million people took part in a march, while the police put the figure at 340,000. The tabling of the Bill was postponed indefinitely last Saturday, but many fear it could be reintroduced when public pressure eases.

The government has said the aim is to prevent the city from becoming a haven for international fugitives, and the law has safeguards. Last Saturday, Mrs Lam said her administration had already made major concessions to ensure political cases would not be considered and that human rights safeguards met international standards.

Mrs Lam has been accused by protesters of being arrogant, ignorant of the wishes of Hong Kongers and aloof. She apologised on Sunday evening, promising to adopt a "sincere and humble attitude".

Chinese Foreign Ministry spokesman Lu Kang said yesterday that China will continue to support Mrs Lam.

Critics had accused the police of heavy-handed tactics during a June 9 mass protest that descended into violence when protesters stormed the Legislative Council. The violence was repeated last Wednesday, the day the Bill was to be debated, when the police fired rubber bullets and tear gas at demonstrators who surrounded the government buildings and charged at officers.

Hong Kong stocks closed up yesterday, leading most Asian markets higher after last week's losses, as investors cheered a decision by the city's government to suspend plans for the controversial extradition Bill.

• Additional reporting by Elizabeth Law