Raid on the Mintz Group office comes as China prepares to hold its annual economic forum.

“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 a statement on Friday, the Reuters news agency reported.

“Mintz Group received no advance notice of the actions taken in Beijing this week, nor has the company received any official legal notice regarding a case against the company. We are confident that we and our employees have done nothing wrong.”

Reuters, citing an anonymous company source, had earlier reported that the office was raided on March 20 and the detained staff were being held incommunicado in a location outside of Beijing.

Criminal suspects in China can be held for months or even years at a time without being charged or having access to legal representation.

The raid comes as Beijing prepares to host the annual China Development Forum, billed as China’s Davos, from tomorrow in person for the first time since the COVID-19 pandemic.

Apple CEO Tim Cook, Pfizer CEO Albert Bourlaother and Mercedes-Benz Chairman Ola Kallenius are among the high-profile executives expected to attend the event.