The Centers for Disease Control and Prevention (CDC) has been ordered to immediately halt all collaborations with the World Health Organization (WHO), according to a memo obtained by the Associated Press. 

The memo was reportedly sent to senior leaders of the agency by CDC official John Nkengasong on Sunday, just days after President Donald Trump issued an executive order withdrawing the U.S. from the United Nations (UN) agency. 

According to the memo, the stop-work policy applied to “all CDC staff engaging with WHO through technical working groups, coordinating centers, advisory boards, cooperative agreements or other means — in person or virtual.” Visiting WHO offices also became prohibited until “further guidance.”

FOX News reached out to the CDC and the Department of Health and Human Services for comment, but they did not immediately respond.

The logo and building of the World Health Organization (WHO) headquarters in Geneva, Switzerland, on April 15, 2020.  (Martial Trezzini/Keystone via AP, file)

“People thought there would be a slow withdrawal. This has really caught everyone with their pants down,” Klausner continued.

According to a White House statement on America’s withdrawal, the WHO demands unfair and heavy payments from the U.S. disproportionate to other countries, such as China. 

“China, with a population of 1.4 billion, has 300 percent of the population of the United States, yet contributes nearly 90 percent less to the WHO,” the statement said.

President Donald Trump signs executive orders in the Oval Office on Jan. 20, 2025, in Washington, D.C. Trump has issued an order to withdraw the U.S. from the World Health Organization (WHO). (Anna Moneymaker/Getty Images)

During a rally in Downtown Las Vegas on Saturday, Trump said the U.S. pays $500 million a year while China pays $39 million. However, the prospect of rejoining the organization is possible if WHO can “clean it up a bit.”

“They offered me at $39 million, they said ‘We’ll let you back in for $39 million,’ they’re going to reduce it from [$500 million] to [$39 million], and I turned them down, because it became so popular I didn’t know if it would be well received even at [$39 million], but maybe we would consider doing it again, I don’t know, they have to clean it up a bit.”

FOX News’ Alec Schemmel and The Associated Press contributed to this report.