US President Donald Trump has said he is going to halt funding to the World Health Organization (WHO) because it has "failed in its basic duty" in its response to the coronavirus outbreak.
He accused the UN agency of mismanaging and covering up the spread of the virus after it emerged in China, and said it must be held accountable.
In response, the UN's chief said it was "not the time" to cut funds to the WHO.
Mr Trump has been under fire for his own handling of the pandemic.
He has sought to deflect persistent criticism that he acted too slowly to stop the virus's spread by pointing to his decision in late January to place restrictions on travel from China.
He has accused the WHO of having "criticised" that decision and of being biased towards China more generally.
"I am directing my administration to halt funding while a review is conducted to assess the World Health Organization's role in severely mismanaging and covering up the spread of the coronavirus," Mr Trump told a news conference at the White House on Tuesday.
The US is the global health body's largest single funder and gave it more than $400m in 2019.
A decision on whether the US resumes funding will be made after the review, which Mr Trump said would last 60 to 90 days.
The WHO is yet to directly respond but UN Secretary General António Guterres said the international community should be uniting "in solidarity to stop this virus".
"It is my belief that the World Health Organization must be supported, as it is absolutely critical to the world's efforts to win the war against Covid-19," he said.
Germany's foreign minister tweeted that strengthening the "under-funded" WHO was one of the best investments that could be made at this time.-BBC