Chinese authorities warned of a sweeping crackdown on "zero covid" protesters and security forces conducted random spot-checks on the streets of major cities, amid widespread confusion over whether Beijing was making a serious attempt to relax its harshest coronavirus measures.

Communist Party leaders, who had otherwise avoided directly mentioning the mass rallies challenging their zero covid policy, said for the first time that they would "resolutely crack down" on the demonstrations.

Chen Wenqing, a former intelligence officer who is head of the Central Political and Legal Affairs Commission, the Communist Party's top decision-making body for law enforcement policy, said Tuesday that authorities would act against "infiltration and sabotage activities by hostile forces as well as on illegal or criminal acts that disrupt social order."

Protests across major cities began last week after a deadly blaze in the far northwestern region of Xinjiang. Many Chinese think the tragedy was worsened because first responders were slowed by distancing measures; local authorities deny the allegations. But three years of living with draconian lockdowns, mass testing and the risk of being sent to spartan centralized quarantine facilities sent many to the edge, triggering extremely rare national demonstrations that occasionally called for the ouster of the Communist Party.

Chen's warning, coupled with the detention of suspected protesters and a ramped-up police presence in major cities, came as demonstrations largely fizzled out on Monday and Tuesday.

Two people in Shanghai told The Washington Post that their colleagues and loved ones were interrogated by police early this week after joining weekend protests against the zero covid policy, which also served as a vigil for the 10 people who died in the Xinjiang fire.

One demonstrator was held incommunicado for 24 hours from Monday to early Tuesday, as family and colleagues frantically searched for him. He was released from a police station early Tuesday, said a co-worker, also named Chen, who attended the protests with him.

Yang, a 27-year-old who attended a weekend rally in the resort town of Dali, where people marched on downtown streets and sang protest anthem "The Internationale," said he was visited by police officers at home. Three of his friends, students at a local university, were told by their school to provide written accounts of their activities on threat of expulsion.

"For me, it was just verbal warning from the police," he said. "I told them I'm a real patriot and I did everything only because I wanted my country to get better."

The people spoke to The Post on the condition that only their last names be used out of fear of reprisal.

In Beijing and Shanghai, police checked the phones of people in the vicinity of protest sites for the messaging app Telegram and virtual private networks, according to a WeChat post Wednesday by Qu Weiguo, an English-language professor at Fudan University in Shanghai. Demonstrators had used these internet services to avoid censors and get around China's "Great Firewall." Qu's post appeared to have been removed by censors within an hour of publication.

China tightened its already rigid censorship regime after a major Communist Party meeting last month. Under regulations that take effect Dec. 15, users who repost or merely like a post that authorities deem harmful could face penalties such as account suspension, although it's unclear how that would be implemented. Access to super-apps such as WeChat, which have functions beyond social networking, is seen as essential for daily urban life in China.

White House press secretary Karine Jean-Pierre said at a news conference Tuesday that Chinese citizens "have a right to peacefully protest without fear."

Asked by a reporter whether the United States planned on using tools to help Chinese internet users circumvent the Great Firewall, Jean-Pierre said she did not have any new information.

Chinese nationalist commentators have suggested, without providing evidence, that Western governments orchestrated the recent rallies. Foreign Ministry spokesman Zhao Lijian on Tuesday criticized the BBC for its China coverage, asking if it "is the job of BBC journalists to report news or fabricate news?"

The broadcaster said Chinese authorities beat and briefly detained one of its journalists, who was reporting on a protest Sunday.

For many Chinese, contradictory messaging on coronavirus control measures has added to the confusion. The Communist Party recently said it would seek to reduce the burden of coronavirus measures on daily life, though it did not offer a road map, and local officials are still under pressure to curb widespread transmission of the virus.

The manufacturing hub of Zhengzhou, home to the world's largest iPhone factory, announced late Tuesday that it would lift a lockdown. Hours later, however, it published a list of 1,531 high-risk residential compounds that would still be under tight restrictions. The local government listed just 15 low-risk compounds in the entire city.

And while the southwestern city of Chengdu called off the construction of a 10,000-bed centralized quarantine facility, the eastern province of Shandong is spending hundreds of millions of dollars to build temporary hospitals and quarantine facilities that can house more than 200,000 people, Chinese financial publication Caijing reported Tuesday.

Shanghai Disney Resort, which has been shut multiple times this year, said it would temporarily close again on Tuesday - just four days after a Nov. 25 reopening.

Reports in state media, however, stirred hope that China might soon shift its approach toward the pandemic. The propaganda department of Zhejiang province published a widely circulated article that urged local governments to focus on containing the virus instead of containing residents. Beijing News, a government-run newspaper, published interviews with a dozen people who recovered from covid-19, in a possible signal that authorities are trying to normalize the disease.

The haphazard way that authorities have handled the pandemic this year has been a major drag for the Chinese economy. Manufacturing activity contracted further in November, according to the National Bureau of Statistics. More restaurants went out of business in the first half of 2022 than the whole of 2021, according to Qichacha, a Chinese business data provider.

"When I saw the young people chanting slogans that night, I was moved," said Xu, a restaurant owner in the central city of Changsha, who spoke on the condition that he be identified only by his last name. "It just occurred to me, my place is going bankrupt not because I didn't work hard enough. Nobody is going to come here if the controls go on."

The Washington Post's Vic Chiang in Taipei, Taiwan, contributed to this report.