A visit by a team of experts working with the World Health Organization (WHO) learned at "the last minute" on Tuesday that they will not be able to travel to China as planned to research the origins of the coronavirus.
"Today we learned that Chinese officials have not yet finalised the necessary permissions for the team's arrival in China. I am 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," read a quote from WHO director general Tedros Adhanom, which was tweeted by the agency.
Michael Ryan, head of the WHO's emergencies programmed called the delay "frustrating."
Negotiations between the WHO and China about the mission have lingered on for months. China will not let the team begin its work until every member is signed off individually.
The virus' spread was first recorded late in 2019 in and around Wuhan, China, which is widely believed to be the starting point of the pandemic. But China has been pushing back against the idea that the pandemic started there, with state media routinely citing unsubstantiated reports that the coronavirus had been reported in other parts of the world before the Wuhan outbreak.
From animals to humans
The WHO team wants to focus its research on Wuhan. It is believed the virus spread from animals to humans at a market in the city.
Of the two members of the WHO team already on their way to China, one has returned home, while another broke off the trip in a third country. Two further members only got news of the cancellation with minutes to spare.
Despite earlier assurances, Beijing said that it did not have their entry papers.
Ryan said Tedros has once again told China how urgent the mission is. Chinese officials have now said the needed documents will be processed quickly.