HONG KONG — Protesters in Hong Kong, fearful that their civil liberties are under threat, are gathering in numbers not seen for years in this semiautonomous Chinese territory.

They are protesting a proposed law that would allow criminal suspects to be sent to jurisdictions with which Hong Kong has no extradition agreement, including mainland China, where the legal system is controlled by the ruling Communist Party. Critics of the law worry that it could be used to detain or intimidate activists, journalists and others who run afoul of Beijing.

[Why are people protesting in Hong Kong? Catch up here.]

A protest on Sunday drew more than a million people, organizers said, in a city of about seven million. The Hong Kong government, which is dominated by pro-Beijing lawmakers, said on Monday that the bill would not be withdrawn. In response, opponents of the law gathered outside the Hong Kong legislature starting Tuesday night, forcing lawmakers to delay a debate on the bill that was scheduled for Wednesday.

The protests intensified on Wednesday afternoon, with protesters hurling bricks, bottles and umbrellas as they clashed with the police. Riot police officers responded by deploying tear gas against protesters who tried unsuccessfully to storm the Legislative Council.