But the intelligence agency cautioned it had “low confidence” in this determination.

A spokesperson said that a “research-related origin” of the pandemic “is more likely than a natural origin based on the available body of reporting”.

The decision to release that assessment marks one of the first made by the CIA’s new director John Ratcliffe, appointed by Donald Trump, who took over the agency on Thursday.

Ratcliffe, who served as director of national intelligence during President Trump’s first term, has long favoured the lab leak theory, claiming Covid most likely came from a leak at the Wuhan Institute of Virology.

The institute is a 40-minute drive from the Huanan wet market where the first cluster of infections emerged.

In an interview with Breitbart News published on Friday, Ratcliffe said he wanted the CIA to abandon its neutral stance on the origins of the virus and “get off the sidelines”.

“One of the things that I’ve talked about a lot is addressing the threat from China on a number of fronts, and that goes back to why a million Americans died and why the Central Intelligence Agency has been sitting on the sidelines for five years in not making an assessment about the origins of COVID,” he said.

“That’s a day-one thing for me.”

But officials told US media that the new assessment was not based on new intelligence and predates the Trump administration. The review was reportedly ordered in the closing weeks of the Biden administration and completed before Trump took office on Monday.

The review offered on Saturday is based on “low confidence” which means the intelligence supporting it is deficient, inconclusive or contradictory.

There is no consensus on the cause of the Covid pandemic.

Some support a “natural origin” theory, which argues the virus spread naturally from animals, without the involvement of any scientists or laboratories.

The lab leak hypothesis specifically has been hotly contested by scientists, including many who say there is no definitive evidence to back it up. And China has in the past dismissed the lab claim as “political manipulation” by Washington.

Still, the once controversial theory has been gaining ground among some intelligence agencies.

In 2023, FBI Director Christopher Wray told Fox News it was his bureau’s assessment that “the origins of the pandemic are most likely a potential lab incident”.

In a statement on Friday, the United States Department of Justice said Asif William Rahman, 34, pleaded guilty to two counts of “willful retention and transmission of classified information” related to national defence.

He is scheduled to be sentenced on May 15 and faces a maximum penalty of 10 years in prison for both counts, according to a plea agreement.

“Mr. Rahman betrayed the trust of the American people by unlawfully sharing classified national defense information he swore an oath to protect,” Assistant Attorney General Matthew G Olsen said in the statement.

“Today’s guilty plea demonstrates that the Justice Department will spare no effort to swiftly find and aggressively prosecute those who harm the United States by illegally disclosing our national security secrets.”

The FBI arrested Rahman — whom the US government said was an employee of the CIA since 2016 and had a Top-Secret security clearance — in Cambodia in November.

US media outlets reported at the time that American officials accused him of leaking documents prepared by the National Geospatial-Intelligence Agency (NGA), which analyses images and information collected by US spy satellites.

The NGA also conducts work in support of secret US military operations.

The documents, which appeared in October on a channel of the Telegram messaging app, had noted that Israel was moving military assets in place to conduct a military strike in response to a ballistic missile attack by Iran on October 1.

Iran said those launches were carried out in retaliation for the assassination of Hamas leader Ismail Haniyeh in the Iranian capital, Tehran, as well as the killing of a senior Iranian military official.

Israel carried out its own attack on multiple sites in Iran in late October.

Citing court documents, the Justice Department said on Friday that Rahman had accessed and printed two documents marked “Top Secret” that contained national defence information “regarding a US foreign ally and its planned actions against a foreign adversary”.

“Rahman removed the documents, photographed them, and transmitted them to individuals he knew were not entitled to receive them,” the department said.