UNITED NATIONS — United Nations Secretary-General Antonio Guterres is responding to U.S. President Donald Trump’s threatened cutoff of funding to the World Health Organization, saying the U.N. agency “is absolutely critical to the world’s efforts to win the war against COVID-19” and must be supported.

The U.N. chief says the coronavirus pandemic “is unprecedented in our lifetime and requires an unprecedented response.”

“Obviously, in such conditions, it is possible that the same facts have had different readings by different entities,” Guterres says.

Once the pandemic ends, he says, there must be an investigation of how it emerged and spread so quickly as well as the reactions of all those involved in the crisis so lessons can be learned.

“But now is not that time,” the secretary-general says. “Now is the time for unity, for the international community to work together in solidarity to stop this virus and its shattering consequences.”

U.N. spokesman Stephane Dujarric says Guterres has been in touch with the World Health Organization and the U.S. administration “at various levels.”

The U.S. contributed nearly $900 million to WHO in 2018-2019, according to the agency’s website, representing about 20 percent of its $4.4 billion budget for those years.