Police have fired rubber bullets and tear gas in Hong Kong at demonstrators amid anger at a new bill to allow extradition to mainland China.
Protesters blocked key roads around government buildings and threw bricks and projectiles at police.
They are concerned the new laws could target political opponents of Beijing, and fear human rights abuses in China’s legal system.
Hong Kong’s Chief Executive, Carrie Lam, condemned the “organised riots”.
“The rioting actions that damage peaceful society, ignoring law and discipline is unacceptable for any civilised society,” she said in a video statement.
Officials say 72 people aged between 15 and 66 have been injured so far, with two men in critical condition.
The government is still backing the bill and it is expected to pass its final vote on June 20.
It has promised legally binding human rights safeguards and other measures should alleviate concerns.
But Hong Kong’s Legislative Council (LegCo) has now delayed its second reading.
The rallies against the extradition bill are the biggest since the territory was handed back to China by the British in 1997.
Protests had been largely peaceful ahead of the scheduled debate of the bill – but on Wednesday, they escalated as activists tried to storm government buildings.
One young protester wearing a black mask and gloves, told news agency AFP that they would not leave until “they scrap the law”.
Rights groups including Amnesty have accused police of using excessive force, but Police Commissioner Stephen Lo Wai-chung said police had “no choice”.
As night fell, protesters remained in some streets behind makeshift barricades.
Meanwhile, a Chinese foreign ministry spokesman has described reports that security forces from the mainland could be sent to Hong Kong as “fake news”.
Geng Shuang said such reports were “rumours to fool people so as to create panic”.
Police said they were also investigating death threats made against Ms Lam.
In a tearful interview with local TV, Ms Lam dismissed accusations that she had “sold out” Hong Kong.
“I have grown up here with all the Hong Kong people,” she said. “My love for this place has led me to make many personal sacrifices.”
There has been very limited media coverage of events in Hong Kong on the mainland. Search results are either blank or toe the Beijing line. –BBC