US President Donald Trump has appeared to undercut his own intelligence agencies by suggesting he has seen evidence coronavirus originated in a Chinese laboratory.
Earlier the US national intelligence director’s office said it was still investigating how the virus began.
But the office said it had determined Covid-19 “was not manmade or genetically modified”.
China has rejected the lab theory and criticised the US response to Covid-19.
Since emerging in China last year, the virus has killed 230,000 people worldwide including 63,000 in the US.
The pandemic has seen at least 3.2 million people infected, a million of them Americans, since the virus spread from the city of Wuhan.