The Central Intelligence Agency has assessed that the Covid-19 pandemic is “more likely” to have emerged from a lab rather than from nature, an agency spokesperson said on Saturday.

The agency had for years said it could not conclude whether Covid-19 was the result of a lab incident or it originated in nature. But in the final weeks of the Biden administration, former CIA Director William Burns asked CIA analysts and scientists to make a clear determination, stressing the pandemic’s historical significance, according to a senior US official.

The CIA says it has “low confidence” in its assessment that a “research-related origin of the Covid-19 pandemic is more likely” and notes in its statement that both scenarios - lab origin and natural origin - remain plausible.

The Chinese embassy in Washington did not immediately respond to a request for comment.

It was unclear the extent to which the agency has collected new intelligence on Covid-19’s origins and whether that new evidence was used to formulate the latest assessment.

China’s government says it supports and has taken part in research to determine Covid-19’s origin, and has accused Washington of politicizing the matter, especially because of efforts by US intelligence agencies to investigate.

Beijing has said claims that a laboratory leak likely caused the pandemic have no credibility.

In an interview with Breitbart following his confirmation by the US Senate on Friday, CIA Director John Ratcliffe said one of his first priorities was getting his agency to make a public assessment on the pandemic’s origins.

“That’s a day-one thing for me,” he said. “I’ve been on record as you know in saying I think our intelligence, our science, and our common sense all really dictate that the origins of Covid was a leak at the Wuhan Institute of Virology.”