A team from the World Health Organization (WHO) that was due to investigate the origins of Covid-19 in the city of Wuhan have been denied entry to China.
Two members of the team were already on their way to the country, but failed to gain entry due to a lack of visa clearances, according to the WHO.
The impending probe was agreed by Beijing after months of negotiations with the WHO, but China said that details of the visit, including dates, were still in the process of being arranged.
WHO chief, Tedros Adhanom Ghebreyesus, said he was “very disappointed” that China had failed to finalise the permissions for the team’s arrival in the country, particularly given that two members of the team were already in transit, and others were unable to travel at the last minute.
It was announced last month that the investigation would begin in January 2021, and two members of the international team departed for China early on Tuesday (5 Jan).
WHO emergencies chief, Mike Ryan, said that one had now turned back and one was in a third country, according to Reuters news agency.
Mr Ghebreyesus said that he has been assured that China is speeding up the procedure to allow the team entry and stressed that the visit “is a priority for the WHO and the international team”.
Chinese foreign ministry spokesperson, Hua Chunying, told the BBC that "there might be some misunderstanding" and "there's no need to read too much into it".
She explained: "Chinese authorities are in close co-operation with WHO but there has been some minor outbreaks in multiple places around the world and many countries and regions are busy in their work preventing the virus and we are also working on this.
"Still we are supporting international co-operation and advancing internal preparations.
“We are in communication with the WHO and as far as I know with dates and arrangements we are still in discussions."
The WHO is aiming to send a team of 10 international experts to China for several months in order to probe the animal origins of the Covid-19 outbreak, and determine how the virus first crossed over to humans.
The virus was first detected in the city of Wuhan in central Hubei province in late 2019, with the initial outbreak linked to a market selling exotic animals for meat.
It has been suggested it was there that the virus made the leap from animals to humans, although the origins of Covid-19 still remain highly contested, with some believing the market may have just amplified transmission.
Some research has suggested that coronaviruses capable of infecting humans may have been circulating undetected in bats for decades, but it is not yet known what intermediate animal host transmitted the virus between bats and humans.