The World Health Organization on Friday urged all countries to share intelligence about the origins of Covid-19 after a United States agency claimed that the virus was likely leaked from a Chinese laboratory.

“I have written to, and spoken with, high-level Chinese leaders on multiple occasions, as recently as just a few weeks ago,” the global health body’s Director-General Tedros Adhanom Ghebreyesus said.

US Federal Bureau of Investigation Director Christopher Wray told Fox News this week that the agency “has for quite some time now assessed that the origins of the pandemic are most likely a potential lab incident in Wuhan”.

On February 26, the Wall Street Journal had reported that the US Department of Energy had found the virus was most likely the result of a lab leak in Wuhan but could only reach that conclusion with “low confidence”.

The first Covid infections were recorded in Wuhan in late 2019 and the central Chinese city hosts a leading virus laboratory, the Wuhan Institute of Virology.

China, however, has denied the Federal Bureau of Investigation chief’s claims, describing it as a smear campaign against Beijing.

On Friday, the World Health Organization chief said that “all hypotheses on the origins of the virus remain on the table”. Tedros said that the politicisation of the investigation was making the scientific work harder and the world less safe.

He also stressed that there was a moral imperative to find out how the pandemic began for the sake of the millions who lost their lives to Covid-19 and those living with long Covid.

Tedros said that the global body did not wish to apportion blame and only wants to prepare for future epidemics and pandemics.

Maria Van Kerkhove, the World Health Organization’s Covid-19 technical lead, said the authorities have contacted the US mission in Geneva for more information.

She added, “Our work continues on this space: looking at studies in humans, looking at studies in animals, looking at studies at the animal human interface, and also looking at potential breaches in biosafety and biosecurity for any of the labs that were working with coronaviruses, particularly where the first cases were detected in Wuhan, China, or elsewhere.”