Hong Kong Police Arrest Dozens of Opposition Politicians

The arrests, which began about 6 a.m. at the homes of those arrested, were related to unofficial primaries held last year by the democratic camp to choose candidates ahead of planned legislative elections, some of those arrested said on social media. Police declined to comment.

“It’s a blatant attempt to intimidate pro-democracy activists and warn people not to engage in politics and collaboration,” said Emily Lau, who served seven terms as a legislator and is a former chairperson of the city’s Democratic Party.

Rounding up opposition figures in large numbers signals Beijing’s determination to quash opposition in the city despite a chorus of international condemnation. The Trump administration has repeatedly criticized China for undermining the city’s partial autonomy through arrests, disqualification of election candidates and other actions.

“The sweeping arrests of pro-democracy demonstrators are an assault on those bravely advocating for universal rights,” Antony Blinken, President-elect Joe Biden’s nominee for secretary of state, said in a post on Twitter. “The Biden-Harris administration will stand with the people of Hong Kong and against Beijing’s crackdown on democracy.”

Activists say Hong Kong risks squandering its reputation as a safe base for international businesses and expatriate professionals as rights to free speech and assembly are eroded. Street protests withered last year amid the coronavirus pandemic that police cited to prohibit such gatherings, but some lawmakers and other political opponents continued to speak up to defend people’s freedoms and criticize the government.

The city’s chief executive, Carrie Lam, has hailed the national security law for bringing stability back to the city. In December, she told the audience of The Wall Street Journal’s CEO Council Summit that, with law and order in the city restored by the security law’s implementation, Hong Kong has promising prospects and it is an “opportune time” for businesses to invest in the city.

Wednesday’s arrests represent a huge increase in those apprehended under the new law, which gives authorities broad latitude to prosecute people for collusion, secession and sedition. Before Wednesday, around 40 people had been arrested under the law, while state media revealed about 30 exiled activists are on a wanted list.

Prosecutors have so far brought charges under the security law against four of those arrested, including media mogul Jimmy Lai.

One of the people arrested Wednesday, Ng Kin-wai, recorded his arrest in a Facebook live stream. In the recording, a police officer said he was accused of subversion for participating in the primaries that aimed to cause Hong Kong’s government to dysfunction, an offense under the national security law.

In July, the opposition camp took part in self-organized primaries, less than two weeks after the security law was imposed, as part of a political strategy to select preferred candidates for scheduled elections in September. The event was aimed at gaining a majority in the 70-seat legislature, which some participants said they would use to block government legislation. Organizers said then that about 600,000 members of the public cast votes.

Mrs. Lam, the city’s chief executive, warned at the time that the opposition’s goal of objecting to every policy initiative of the government may fall into the category of subverting state power.

Many who ran in the primaries were told weeks later that their candidacies for the September elections were invalid, with authorities citing concerns over their loyalty to the city and its constitution. Shortly after the disqualifications, the government postponed the elections by a year, citing the coronavirus pandemic, and extended the sitting legislature.

In November, Beijing forced the expulsion of four pro-democracy members from the interim legislature for being disloyal. It sparked the pro-democracy camp’s resignation en masse and was criticized by some foreign governments as an evisceration of elected institutions.

Wednesday’s arrests heightened fears that opposition is being curtailed in the former British colony that already had limited democratic institutions.

“This is disgraceful and ridiculous. How can people taking part in a primary election to select candidates be subversive?,” Ms. Lau, the former lawmaker, said.

Those arrested on Wednesday included politicians from a number of pro-democracy parties, according to social media accounts. Among them were former legislators James To and Alvin Yeung and new-generation activists such as former journalist Gwyneth Ho and Lester Shum, who was a student leader during a 79-day street occupation in 2014 known as the Umbrella Movement.

Local media reported authorities had arrested legal academic Benny Tai, one of the primaries’ organizers; and top pollster Robert Chung, who assisted in the logistics. Authorities also visited the home of Joshua Wong, who is currently serving a prison sentence for organizing a protest in 2019, according to social-media posts from friends writing on his behalf.

Sunny Cheung, a participant in the primaries who has since fled overseas, said the arrests show his decision to leave the city after the national security law came into effect was right, though painful.

“This is obviously a political purge to erase the whole pro-democracy camp,” said Mr. Cheung. “The purge will continue.”

—Wenxin Fan contributed to this article.

Write to Natasha Khan at natasha.khan@wsj.com