Beijing and Shanghai reported new clusters of COVID-19 infections on Thursday, involving a bar in Beijing and a beauty salon in Shanghai. The cases show the insidious risks of a rebound of infections still exist, the two cities' health officials warned.

As of 3 pm on Thursday, Beijing had reported three new locally transmitted cases at the community level, breaking the five straight days of zero such cases.

According to Liu Xiaofeng, deputy director of the Beijing Center for Disease Prevention and Control, who spoke at a news conference on Thursday afternoon, the three cases are from three different districts－Xicheng, Fengtai and Huairou. The new cases have brought the total number of infections in Beijing's latest outbreak to 1,834 since April 22.

"The new cluster involved several bars in the city and was found during nucleic acid testing. Epidemiological investigations are being conducted," he said.

In addition to the three confirmed cases, three people in Changping, two in Chaoyang and one in Huairou district tested positive for the virus on Thursday. Many had been to a bar in the Sanlitun area of Chaoyang district, according to the authority.

Facing a sudden infection cluster, Beijing's top epidemic control and prevention work group held a meeting presided over by Beijing Party Secretary Cai Qi on Thursday morning, stressing that related departments should accelerate the epidemiological investigation and involved districts should take swift action to contain the epidemic and avoid the virus spreading.

Beijing will conduct a citywide check on epidemic control and prevention procedures in all bars, internet cafes and karaoke venues to ensure safety measures have been strictly implemented, the officials said.

Starting on Thursday afternoon, all entertainment venues, internet cafes, underground gyms and sports facilities in Chaoyang were ordered to suspend operation to avoid infection risks, said the district government.

Li Ang, deputy head of the Beijing Health Commission, said that despite the cases, Beijing's epidemic situation has been effectively contained in general terms.

The authority now requires a negative nucleic acid test from within 72 hours before entering public places, instead of the previous 48-hour requirement, in order to ease the testing burden on people.

Shanghai reported six locally transmitted COVID-19 infections outside of quarantine and locked-down communities, including three working at a downtown beauty salon, on Thursday.

As of 4 pm Thursday, 655 close contacts and 1,230 secondary close contacts of the infections have been traced and put under quarantine. All their nucleic acid test results that have been returned have come back negative so far, Zhao Dandan, deputy director of the Shanghai Health Commission, said at a news briefing.

"Since June 1, when Shanghai lifted most epidemic prevention and control measures, scattered infections have emerged, especially in old neighborhoods and in the service industry," said Zhao, adding risks of a rebound of the epidemic still exist.

Wang Hongwei, deputy head of Xuhui district, where the beauty salon is located, said the salon has 16 employees altogether and 481 customers have been tracked down.

"We'll further require all service businesses to only accept customers with valid nucleic acid test results from within 72 hours and a normal body temperature. All the workers and customers must wear masks throughout the process," he said.