Four separate transmission chains have been found in the recent outbreak of COVID-19 in Beijing, including three related to cases from regions outside the city and a cluster involving a store that sold imported clothing, officials said on Thursday.

Beijing reported five new locally transmitted COVID-19 cases and two asymptomatic carriers from 4 pm Wednesday to 4 pm Thursday, bringing the total number of infected people to 25 in the latest outbreak since April 3, Pang Xinghuo, deputy director of the Beijing Center for Disease Prevention and Control, said at a news conference on Thursday.

"All the new cases were detected among people under controlled management," she said. "Among all 25 infected cases, 22 are related to the store."

The 22 cases include nine employees of the clothing store in Beijing's Chaoyang district, seven family members of those employees, two customers who visited the store and four other related people.

"Epidemiological investigation shows an infected case had symptoms of COVID-19 on April 1, causing at least three generations of transmission of the virus," she said. "The spread of the virus is very fast, as it is highly contagious."

"The transmission chain has been extended, and we can't rule out the possibility of more new cases," she added.

"During a nucleic acid test conducted on two batches of imported clothing on Wednesday, results came back positive," she said. "Epidemiological investigation and work on tracing close contacts have been carried out."