The Trump administration on Tuesday gave notice to Congress and the United Nations that the U.S. is formally withdrawing from the World Health Organization.

The news was relayed in a tweet from Sen. Robert Menendez, D-N.J., the top Democrat on the Senate Foreign Relations Committee.

"Congress received notification that POTUS officially withdrew the U.S. from the ⁦‪@WHO⁩in the midst of a pandemic. To call Trump's response to COVID chaotic & incoherent doesn't do it justice. This won't protect American lives or interests—it leaves Americans sick & America alone," the tweet from Menendez said.

The U.S. also sent a short letter to the U.N. about the withdrawal, CNN reported. The letter sent to the U.N. will reportedly trigger a one-year timeline for the withdrawal.

President Trump has been frequently critical of the WHO and said he would pause U.S. funding for the agency in April. He has claimed that the WHO has not been transparent about the nature of the coronavirus, and said the agency has an “alarming lack of independence” from China.

Trump on May 29 announced that the U.S. would sever ties with the global health body and that “China has total control over” the organization. The comments came 10 days after he sent a has sent a letter to WHO director-general Tedros Adhanom Ghebreyesus that warned of permanent cuts.

The U.S. is the WHO's biggest funder, paying roughly $450 million in membership dues.

Democrats have criticized Trump’s move to withdraw from the WHO, as they believe the White House is trying to shift the blame from his own administration’s response to the pandemic. The American Medical Association, the largest formal group of doctors in the U.S., has urged the White House in the “strongest terms possible” to reverse the decision.

The U.S. currently has the most cases of the virus in the world. As of 3:55 p.m. ET on Tuesday, there are 2,966,409 COVID-19 cases in the country and a death toll of 130,902, according to Johns Hopkins University.