Beijing's health authority held talks with all third-party nucleic acid testing firms in the city on Friday, as illegal testing activity was recently reported and authorities are determined to crack down on violations.

Yang Daqing, deputy director of the Fangshan district health commission in Beijing, together with two other officials－Jin Changhao and Xing Man－are under investigation for alleged serious violations, according to an announcement from the Beijing authority for discipline inspection on Friday.

The announcement said they are related to the case of Beijing Pushi Medical Laboratory Co, which reportedly provided test result data that was obviously lower than the number of samples collected.

Last week, Beijing police took measures against six people related to the lab, whose business license has been revoked. The authority has filed a case charging obstruction of work involving the prevention and control of infectious diseases.

"The government will severely punish test labs that purposely alter the accuracy of results to illegally obtain profits," said Xu Hejian, spokesman of the city government, at a news conference on Friday.

On the same day, Beijing police reported a case involving the Jinzhun Medical test lab, which allegedly diluted samples by mixing multiple tubes together during tests.

"The wrongdoing of the company has affected the accuracy of the test results. The bureau has filed a case against the company for obstructing the prevention and control of infectious diseases," said Pan Xuhong, spokesman for Beijing's public security bureau.

Police took measures against 17 people involved, including the company's 43-year-old legal representative surnamed Wang. The case is under further investigation.

Beijing has carried out several rounds of mass nucleic acid testing in most districts since the outbreak started on April 22. "Test labs and institutions at all levels－including national public labs, city and district level testing bases, as well as third-party institutions－h(huán)ave completed several rounds of testing, which have provided a base of data for measures we have taken to keep the virus from spreading," Li Ang, deputy director of the Beijing Municipal Health Commission, said on Friday.

However, during recent supervision and checks, some testing institutions were found to have carried out highly illegal activities, which has influenced the testing quality and the effect of epidemic control and prevention work, he said.

The health commission will conduct a citywide on-site examination of all testing institutions to strengthen management of the whole procedure.

Meanwhile, multiple departments will jointly work on guaranteeing nucleic acid testing quality, Li said.