The World Health Organization (WHO) says “all available evidence” indicates the Covid-19 coronavirus is not a bio-weapon, but a naturally occurring pathogen, reports Reuters.

At a news briefing in Geneva, a WHO spokeswoman said: “It is probable, likely, that the virus is of animal origin,” most likely bats.

President Donald Trump said last week that his administration is trying to determine if the virus came from a lab in Wuhan, China, where the pandemic first appeared in December.

“All available evidence suggests the virus … [was] not manipulated or constructed in a lab or somewhere else,” the WHO spokeswoman said.

What’s not yet clear, she said, is “how the virus had jumped the species barrier  … but there had ‘certainly’ been an intermediate animal host,” between bats and humans, Reuters says.

The spokeswoman didn’t elaborate on the WHO’s dismissal of suspicions that the coronavirus somehow escaped from the Wuhan Institute of Virology, which has denied rumors both that it “synthesized the virus or allowed it to escape,” the news agency says.

The U.S. is the WHO’s leading donor; last week, Trump said he was suspending that funding.