Beijing on Wednesday said that delays to the mission by World Health Organization experts to visit China to investigate the origins of the coronavirus were “not just a visa issue,” and that talks were underway to fix a specific time, AFP reported.

Health experts from the United Nations body were expected to visit China to trace the origins of the infection, which first originated in Wuhan in Hubei province. The mission, however, has been delayed from time to time with China not allowing the team to enter the country.

Foreign ministry spokesperson Hua Chunying said the matter of origin-tracing was complicated and that China and the WHO were holding talks over the specific date and arrangement for the visit of the expert group. “To ensure the work of the international expert team in China goes smoothly, we have to carry out necessary procedures and make relevant arrangements,” said Hua.

The spokesperson said there was no reason to “overinterpret” the matter, according to Reuters. Hua added that Beijing was “doing its best to create good conditions” for the international expert group to come to China.

She said that experts in the country were also busy dealing with renewed cases of the coronavirus, with many locations entering a “wartime footing” to stop the infection.

On Tuesday, WHO Director General Tedros Adhanom Ghebreyesus expressed disappointment over China not finalising the visit for the arrival of the expert team.

“Today we learned that Chinese officials have not yet finalised the necessary permissions for the team’s arrival in China,” Tedros said. “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.”

He said that the visit was planned as per arrangements jointly developed by the WHO, the Chinse government and the countries through which the team would travel on their way to Wuhan.

The WHO chief said that he has been in touch with senior Chinese officials and told them that the mission was a priority. “I have been assured that China is speeding up the internal procedure for the earliest possible deployment,” he added.

China has regularly denied claims that the virus originated in the country. It had also faced flak from the international community for allegedly covering up the transmission of the disease and for acting too slowly to stop its spread.

In an interview given to state-run Xinhua news agency on January 1, China’s Foreign Minister Wang Yi claimed that the coronavirus pandemic was likely caused by outbreaks outside the country, in an attempt to change the narrative about the infection’s origin.

“We raced against time and were the first country to report cases to the world,” Yi had said. “More and more research suggests that the pandemic was likely to have been caused by separate outbreaks in multiple places in the world.”

Chinese state-run media and officials have pushed alternate theories that the coronavirus could have entered the country through imported frozen food, linked the infection to the United States military and cited research suggesting cases in the US and Italy pre-date those in Wuhan.

Meanwhile, the coronavirus has infected more than 8.63 crore people and killed over 18.67 lakh across the globe, according to the Johns Hopkins University. More than 4.84 crore people have recovered from the infection in the world.