GENEVA (AP) — The World Health Organization says it has received no evidence or data from the U.S. government to back up claims by President Donald Trump and Secretary of State Mike Pompeo that the coronavirus may have originated at a laboratory in the Chinese city of Wuhan.

WHO's emergencies chief, Dr. Michael Ryan, said such claims were "speculative" and reiterated the U.N. health agency's belief that the coronavirus was of natural origin.

He said WHO would nonetheless be "very willing" to receive any information that could point to the origin of the outbreak.

He conceded it would be up to the U.S. government to decide whether and when to share such information.