US President Donald Trump has appeared to undercut his own intelligence agencies by suggesting that he has seen evidence the novel coronavirus originated in a Chinese laboratory.
Earlier, the US national intelligence director's office said it was still investigating the virus' origins. But the office said it had determined COVID-19 "was not manmade or genetically modified", the BBC reported.
China has rejected the lab theory and criticised the US response to COVID-19.
Since emerging in the Chinese city of Wuhan at the end of last year, the coronavirus is confirmed to have infected 3.2 million people and killed more than 230,000.
At the White House on Thursday, Trump was asked by a reporter: "Have you seen anything at this point that gives you a high degree of confidence that the Wuhan Institute of Virology was the origin of this virus?"
"Yes, I have. Yes, I have," said the president, without specifying. "And I think the World
Health Organization should be ashamed of themselves because they're like the public relations agency for China."
Asked later to clarify his comment, he said: "I can't tell you that. I'm not allowed to tell you that."
He also told reporters: "Whether they (China) made a mistake, or whether it started off as a mistake and then they made another one, or did somebody do something on purpose?
"I don't understand how traffic, how people weren't allowed into the rest of China, but they were allowed into the rest of the world. That's a bad, that's a hard question for them to answer."
A leading US media outlet reported on Thursday that senior White House officials have asked the US intelligence community to investigate whether the virus came from a Wuhan research laboratory.
Intelligence agencies have also been tasked with determining if China and the WHO withheld information about the virus early on, unnamed officials told an American news channel on Wednesday, the BBC reported.
In a rare public statement, the Office of the Director of National Intelligence, which oversees US spy agencies, said on Thursday it concurs with the "wide scientific consensus" regarding COVID-19's natural origins.
"The (intelligence community) will continue to rigorously examine emerging information and intelligence to determine whether the outbreak began through contact with infected animals or if it was the result of an accident at a laboratory in Wuhan."
It was the first clear response from American intelligence debunking conspiracy theories - both from the US and China - that the virus is a bio-weapon.
But the possibility that the coronavirus could have inadvertently leaked from a research facility has not yet been disproven.
( With inputs from IANS )