A World Health Organization meeting to rally an international response to the coronavirus pandemic has instead amplified the discord between the United States and China, leaving the U.N. agency caught in the middle and struggling to lead amid the crisis.

The World Health Assembly — an annual WHO meeting that this year transformed into a virtual strategy session for the covid-19 fight — was quickly overshadowed by President Trump’s latest ultimatum in his widening battles with Beijing and the U.N. health organization.

Trump threatened to permanently halt U.S. funding to the WHO and “reconsider” the country’s membership in the U.N. body if it does not “commit to major substantive improvements” within the next 30 days.

In a letter to the WHO posted in a late-night tweet Monday, Trump elaborated on assertions he has been making since April when he suspended U.S. payments to the WHO for 60 days over what he called its “China centric” coronavirus response.

The four-page letter came the same day Chinese President Xi Jinping addressed the assembly by video link. Xi skimmed over China’s handling of the initial outbreak late last year and emphasized its commitment to the global pandemic fight, pledging $2 billion.

The standoff between Trump and Xi took attention away from much of the other news from the assembly, including the WHO agreeing to hold an inquiry into the global response to the coronavirus pandemic.

“The assembly has turned into a political circus,” said Lawrence Gostin, a professor of global health law at Georgetown University who also provides technical assistance to the Geneva-based WHO.

“To see this unfolding in the middle of the coronavirus pandemic is deeply problematic,” he added.

Trump’s letter is clear: Either the WHO make changes, or the United States walks.

But the president did not specify what changes were needed for him to restore U.S. funding, the WHO’s largest single source of money. Trump also said discussions between the United States and the agency’s leaders were underway but gave no details.

The WHO said in a statement that it was “considering the contents of the letter.”

Trump’s central argument is that the WHO’s handling of the crisis cost lives by accepting China’s assessments of the spread and threat in the early weeks.

“It is clear the repeated missteps by you and your organization in responding to the pandemic have been extremely costly for the world,” Trump wrote.

The timeline he lays out, however, mixes legitimate concerns and inaccuracies. It also excludes information about what Trump himself knew and said at the time.

For instance, many governments, researchers and public health experts were baffled that the WHO did not express more skepticism about China’s claims, in mid-January, that there was no evidence of human-to-human transmission.

The letter restated some of these concerns and added new ones — including some that do not hold up to scrutiny.

Trump’s first claim, for instance, is that the WHO “ignored credible reports of the virus spreading in Wuhan in early December 2019 or even earlier.” He cites as evidence information published by the Lancet.

But Richard Horton, chief editor of the publication, said Tuesday that the journal did not publish its first reports on the coronavirus until late January.

The letter also takes aim at the WHO for repeatedly praising China’s “transparency” despite evidence that Chinese officials silenced whistleblowers and undercounted cases.

But the letter does not mention that Trump himself made similar statements. Trump said Jan. 24 that “the United States greatly appreciates [China’s] efforts and transparency,” for instance.

On Feb. 7, Trump said he was not concerned about China covering things up. On Feb. 26, he said China was working “very hard” and said on March 4 that it had the situation under control.

If Trump makes good on his threat, the WHO programs could take a hit.

The United States makes mandatory payments to maintain its membership in the WHO in addition to larger voluntary donations, which in total amount to about 15 percent of the agency’s budget.

The mandatory payment, known as the “assessed contribution,” may prove difficult for Trump to cut without congressional approval.

At greater risk is the “voluntary contribution,” money provided to U.S. agencies for health efforts and then given to WHO programs. The largest share of this money goes to polio eradication, with large chunks to fight vaccine-preventable disease, malaria, tuberculosis, HIV/AIDS and the provision of basic health care.

There are signs the United States is already moving away from the organization. Administration officials have looked to redirect the WHO payments to other nongovernmental public health organizations, The Washington Post reported.

In recent weeks, U.S. officials have appeared to loosen ties with the agency in other ways. The State Department removed mentions of the WHO from virus fact sheets, and staffers were ordered to “cut out the middle man” for public health initiatives previously managed through the WHO.

That move has sparked concerns that the United States could lose influence on the international stage to China.

The Chinese government immediately hit back and said the United States was using China as an excuse to shirk financial obligations that had been jointly determined by the WHO member states.

“The unilateral U.S. move to stop funding is a violation of its own international obligations,” Foreign Ministry spokesman Zhao Lijian told reporters Tuesday in Beijing. “We are still in a critical juncture and supporting the WHO is upholding multilateralism and supporting international anti-pandemic cooperation to save lives.”

The Trump administration, Zhao added, was “trying to mislead the public, smear China and shift blame for its own incompetent response.”

The United States is already less visible in global health diplomacy. Both Trump and Xi were invited to address the World Health Assembly — but only Xi chose to speak.

On Tuesday, Chinese state media revved into gear on official channels and on social media to portray the Chinese president as a world leader who cared for the global “community” and the WHO as an indispensable agency that coordinated the international response and offered technical guidance.

His message to the world, according to state broadcaster anchor Guo Zhijian: “China is sincere, China is responsible, China is contributing.”

The WHO said it welcomed an investigation. “We want accountability more than anyone,” said director general, Tedros Adhanom Ghebreyesus, on Tuesday.

He urged countries to act cooperatively. “Now is the time to act. We need to fight and defeat coronavirus in all continents,” he said.

“We need tests, medicines, and a vaccine, and we need them to be affordable for all.”