Westerners living in the Chinese capital have been warned of possible terror threats in busy shopping areas and nightspots over the Christmas holiday period, U.S. officials said.
The warnings prompted China to dispatch SWAT teams to guard potential targets on Thursday, official Chinese media reported.
"The U.S. Embassy has received information of possible threats against westerners in the Sanlitun area of Beijing, on or around Christmas Day," the U.S. Embassy in Beijing said in an official notice on its website.
"U.S. citizens are urged to exercise heightened vigilance," the statement said, adding: "The U.S. Embassy has issued the same guidance to U.S. government personnel."
Similar warnings were issued by at least three other foreign embassies, including the British and Australian embassies, amid calls for heightened vigilance among Christmas revelers.
Chinese Foreign Ministry spokesman Hong Lei said he was aware of the reports.
"The Chinese government pays great attention to the safety of foreigners," Hong told a regular news conference in Beijing.
According to state-run China Radio International (CRI), Beijing police have issued a yellow alert "to ensure public safety over the Christmas season."
Quoting the Beijing municipal police department's official account on the social media platform Sina Weibo, the report said a yellow alert was the first level of threat after green.
"It means 60 percent of the security personnel in large and medium-sized shopping malls and supermarkets should carry out security checks on suspect personnel, materials and vehicles," CRI said.
It said the authorities have also dispatched additional police patrols in crowded downtown areas like Wangfujin, Nanluoguxiang and Sanlitun, and would be checking rubbish bins "every 30 minutes."
A Beijing-based private security guard surnamed Li said the authorities have no choice but to respond to the warning.
"This is a sensitive time, because it's a festival for westerners," Li said. "The checks and controls are very tight right now, and the antiterrorism police are patrolling the streets."
An employee at a shop in Sanlitun told RFA that the increased security presence was immediately noticeable.
"Yes, there are a lot of security personnel here, even more right here where we are located," the employee said. "They all look pretty specialized."
Official media photographs showed teams of armed police camouflage gear and helmets standing near the Uniqlo store in Sanlitun.
A bar owner surnamed Liang said he had already received official notification of the warnings, adding that police had set up a road block near his business.
"Security checks ... have recently been stepped up here in our neighborhood," the bar owner said. "[The road-blocks] are just opposite our bar."
"Tonight is Silent Night," he said, using the Chinese nickname for Christmas Eve. "[But] we absolutely must carry out security checks on staff and customers."
The warnings come just a day after Beijing hit out at criticism of its draft antiterrorism laws, which U.S. officials fear could be used to target peaceful dissent and religious activities among ethnic minorities in China, particularly the mostly Muslim Uyghur population.
U.S. State Department spokeswoman Gabrielle Price on Tuesday expressed "serious concerns" that China's forthcoming Counterterrorism Law would do more harm than good in fighting terrorism.
"We believe the draft Counterterrorism Law would lead to greater restrictions on the exercise of freedoms of expression, association, peaceful assembly, and religion within China," Price told journalists.
She also criticized Beijing new National Security Law passed earlier this year, as well as a draft foreign nongovernmental organizations (NGO) management law.
Reported by Qiao Long for RFA's Mandarin Service and by Wen Yuqing for the Cantonese Service. Translated and written in English by Luisetta Mudie.