China detains staff, raids office of US due diligence firm Mintz Group

Chinese authorities raided the office of US corporate due diligence firm Mintz Group in Beijing and detained five local staff, the company said, stoking concern among foreign companies in China just as it hosts an international economic forum.

News of the raid and detentions comes as Sino-US relations have spiraled downwards following months of diplomatic tensions, including over the US military downing in February of a suspected Chinese spy balloon and a planned US transit next week by the president of Taiwan, the self-governed island China claims as its territory, Reuters reports.

"We can confirm that Chinese authorities have detained the five staff in Mintz Group's Beijing office, all of them Chinese nationals, and have closed our operations there," the company said in an emailed statement to Reuters late on March 23.

It said it was ready to work with the Chinese authorities to "resolve any misunderstanding that may have led to these events", and that its top concern was the safety and wellbeing of colleagues in China.

"Mintz Group has not received any official legal notice regarding a case against the company and has requested that the authorities release its employees," the company said.

Chinese foreign ministry spokeswoman Mao Ning said on March 24 she was not aware of this case. The Beijing public security bureau did not respond to a request for comment.

A source at the New York-headquartered firm earlier told Reuters on condition of anonymity that the company's local legal counsel said the raid occurred on the afternoon of March 20, and that the employees were being held incommunicado somewhere outside of Beijing.

As per Mintz Group's website, the Beijing office is its only one in mainland China. The website says the company specialises in background checking, fact gathering and internal investigations. Its wide-ranging clients include the National Football League, New York City and The Beatles, according to media reports.