GENEVA (AP) — The head of the World Health Organization said Tuesday that he is "disappointed" that Chinese officials haven't finalized permissions for the arrival of team of experts into China to examine origins of COVID-19.

Tedros Adhanom Ghebreyesus, in a rare critique of Beijing, said members of the international scientific team have begun over the last 24 hours to leave from their home countries to China as part of an arrangement between WHO and the Chinese government.

"Today, we learned that Chinese officials have not yet finalized the necessary permissions for the team's arrival in China," he told a news conference in Geneva.

"I'm very disappointed with this news, given that two members had already begun their journeys and others were not able to travel at the last minute, but had been in contact with senior Chinese officials," he said.

Tedros said he had "made it clear" that the mission was a priority for the U.N. health agency, and that he had been "assured that China is speeding up the internal procedures for the earliest possible deployment."

"We are eager to get the mission underway as soon as possible," he said.

The experts, drawn from around the world, are expected to visit the city of Wuhan that is suspected as the place that the coronavirus first emerged over a year ago.