The World Anti-Doping Agency has suspended the accreditation of Beijing's National Anti-Doping laboratory, weeks after launching a probe into drugs allegations in Chinese swimming.
The laboratory, suspended for a maximum of four months, has 21 days to appeal the decision to the Court of Arbitration for Sport (CAS).
"The suspension, which takes effect immediately, prohibits the laboratory carrying out any WADA-related anti-doping activities including all analyses of urine and blood samples," WADA said in a statement on Thursday.
WADA said the laboratory could apply for reinstatement before the four months was up if it took remedial steps and tackled "non-conformities", without providing details.
China's national anti-doping agency said the laboratory had submitted "two false negative results" during blind tests conducted by WADA in 2015.
"The laboratory will resume testing work after its changes have been reviewed by WADA," the agency said in a statement on its website.
State news agency Xinhua later quoted the laboratory as saying the false negatives were caused by "technical errors" because it had yet to update testing methods to meet WADA's latest requirements.
The laboratory was also negligent in its analysis, it said.
"At present, the laboratory is undergoing a complete review and improvement of its detection methods, in order to meet WADA's latest requirements," Xinhua quoted the lab as saying.
China's anti-doping program has been under scrutiny in recent weeks following a British newspaper report that alleged Chinese swimming had covered up positive drugs tests ahead of trials for the Rio Olympics to avoid a "storm".
The Times report prompted WADA to investigate.
China's anti-doping agency denied there had been a cover-up and said they needed time to test 'B' samples and conduct hearings before releasing further information.
The Chinese Swimming Association subsequently announced it had issued a "warning penalty" to swimmers Wang Lizhuo and An Jiabao after they tested positive for clenbuterol.
A third swimmer Zhao Ying, who also tested positive in an out-of-competition test, was named but had not yet been punished, the association said last month.
