President Javier Milei of Argentina announced plans to withdraw his nation from the World Health Organization on Wednesday, the latest in a series of moves by Mr. Milei that mimic President Trump’s efforts to break with international norms and alliances.

“We will never forget that they were the architects of the draconian lockdowns,” Mr. Milei wrote on X, referring to the W.H.O.’s support for broad quarantines during the pandemic. He called the lockdowns “one of the most egregious crimes against humanity in history.”

“That’s why we have decided to withdraw from such a nefarious organization,” he added, “which acted as the enforcement arm of the largest social control experiment in history.”

President Trump signed an order to withdraw the United States from the W.H.O. in the first hours of his presidency, similarly criticizing the United Nations agency’s handling of the pandemic and the cost of being a member. Mr. Milei has long criticized the W.H.O. — even writing a book condemning pandemic policies in 2020 — but he only decided to pull out of the organization weeks after Mr. Trump did the same.

If the United States and Argentina follow through on their plans, they will join Liechtenstein as the only U.N. member nations that are not also members of the U.N.’s global health alliance.

That reflects Mr. Milei’s effort to align his nation with Mr. Trump’s scorched-earth approach to the international order, even if it comes at the expense of Argentina’s previous allies and partnerships.