© Anthony Kwan/Getty Images Pro-democracy supporters protested outside a Hong Kong police station after Saturday’s arrests of opposition figures.

HONG KONG — More than a dozen leading pro-democracy activists and former lawmakers in Hong Kong were arrested Saturday in connection with the protests that raged in the city last year, the biggest roundup of prominent opposition figures in recent memory.

The arrests signaled a broader crackdown on the antigovernment movement that roiled the semiautonomous city last year, one of the most significant challenges to Communist Party rule in decades. Beijing and pro-government supporters in the city have called for lawmakers to pass national security laws that residents worry would allow mainland authorities to further encroach upon the territory’s civic freedoms.

The high-profile arrests were made as Hong Kong battled to contain the coronavirus outbreak, which has helped quiet down the huge street protests but fueled further distrust of authorities. The virus has halted protests around the world, forcing people to stay home and giving authorities new laws for limiting public gatherings, detaining people with less fear of public blowback while many residents remained under lockdowns or observing limits on their movement.

But the arrests Saturday in Hong Kong, along with a renewed push for national security legislation in the city, could anger protesters and reinvigorate the mass demonstrations that had tapered off.

Fifteen activists between 24 and 81 years old were rounded up on suspicion of organizing, publicizing, or taking part in several unauthorized assemblies between August and October and will face prosecution, police said Saturday without disclosing their names, following protocol.

The arrested democratic heavyweights included veteran lawyers Martin Lee and Margaret Ng; media tycoon Jimmy Lai; and former opposition legislators Albert Ho, Lee Cheuk-yan, and Leung Kwok-hung, political parties and aides said.

While opposition politicians have been included among the thousands of protest-related arrests over the past year, rarely have so many prominent pro-democracy figures been arrested at once.

Lau Siu-kai, vice president of the Chinese Association of Hong Kong and Macao Studies, a powerful Beijing advisory group, said that the arrests Saturday represented an early step toward a broader crackdown by Beijing on the Hong Kong opposition.

The arrests reflect an assessment by Beijing that protests in Hong Kong over the past year pose such a threat to national security that it is worthwhile to defy US threats of retaliation if a crackdown takes place, he said.

“Now Beijing is calling the US’ bluff and taking the initial steps against the Hong Kong opposition, and there will be more steps to shrink their space,” said Lau.

A Communist Party gathering late last year in Beijing, the so-called fourth plenum, set a new tone for policy in Hong Kong that will be carried out this year, Lau said. “This is the time to end the chaos in Hong Kong,” he said. “After the fourth plenum, Beijing is determined to end the chaos in Hong Kong once and for all.”

The arrests followed calls from China’s central government in recent days for Hong Kong to enact a package of national security laws that was last put forward in 2003 but shelved after a mass protest.

Luo Huining, Beijing’s top representative in Hong Kong, said this past week that national security has always been a “prominent shortcoming” since the former British colony’s return to Chinese control in 1997.

He called for urgent work on the “legal system and enforcement mechanism to safeguard national security,” a contentious issue in the city.

Legal experts and critics of Beijing have warned against perceived increased interference in Hong Kong’s local affairs by the Chinese government. The central government’s liaison office in Hong Kong has recently criticized filibustering by pro-democracy legislators, raising concerns that it was violating the “one country, two systems” principle.