It is "dangerous" and "self-destructive" for Washington to withdraw from the World Health Organization (WHO), an agency that "makes the world and America safer" amid the intensifying COVID-19 crisis, experts, lawmakers and group leaders said Tuesday.

The White House has officially moved to pull the US out of the WHO by submitting a notice of withdrawal to the United Nations effective July 6, 2021, officials said.

Stephane Dujarric, the spokesperson for UN Secretary-General Antonio Guterres, said, "The secretary-general ... is in the process of verifying with the World Health Organization whether all the conditions for such withdrawal are met."

The move capped months of threats from President Donald Trump to cut funds and sever ties with the UN health body.

US House Speaker Nancy Pelosi said Trump's official withdrawal was "an act of true senselessness as WHO coordinates the global fight against COVID-19".

"With millions of lives at risk, the President is crippling the international effort to defeat the virus," she wrote on Twitter.

In its 1948 joint resolution to join the WHO, the US Congress set two conditions for withdrawal: to give one year's notice and pay WHO dues.

As of March 31, the US, the largest single government donor to the WHO, was behind in its payment of assessed fees. It owes $198.3 million in membership dues, according to US media reports.

Another Democrat, Congressman Eric Swalwell, also described the decision as "irresponsible, reckless, and utterly incomprehensible". He tweeted that "withdrawing from the @WHO in the midst of the greatest public health crisis of our lifetime is a self-destructive move."

In a statement, Lamar Alexander, the Republican chairman of the Senate health committee, said, "I disagree with the president's decision." He said that the time to look at the mistakes the WHO "might have made" in connection with the novel coronavirus is after the crisis has been dealt with, not in the middle of it.

Globally, there have been nearly 12 million cases of the coronavirus and at least 535,700 known deaths, according to WHO data. About 25 percent of both figures are in the US.

The state of Texas logged a record 10,028 new cases on Tuesday, an indicator of how COVID-19 is making a resurgence nationwide.

Elizabeth Cousens, president and CEO of the UN Foundation, said WHO is the only body capable of leading and coordinating the global response to COVID-19.

"A US withdrawal from WHO would also jeopardize decades of hard-won progress on other critical global health priorities that matter to Americans — from expanding access to vaccines to fighting diseases like polio, malaria and HIV/AIDS and working to strengthen health systems everywhere," she said.

InterAction, an alliance of international NGOs and partners in the US, said in a statement that Trump's move to withdraw from the WHO is "dangerous" and "shortsighted", adding that "the World Health Organization makes the world and America safer in the face of a range of global health threats."

Thomas File Jr., president of the Infectious Diseases Society of America, also said America needs to join with the global scientific community in fighting the virus. It has much to learn from other parts of the world that have reduced infection and death rates.

"Without the WHO, the nation is at higher risk of being inadequately prepared for many health risks of pandemic proportions," he said.

The WHO is so deeply woven into the fabric of US public health that extracting it will be difficult, disruptive and damaging, argued Matthew Kavanagh, an assistant professor of global health at Georgetown University, and his colleague, Mara Pillinger, an associate at the university's O'Neill Institute for National and Global Health Law.

For example, the US is home to 83 different WHO collaborating centers — research institutes, universities and US government agencies that work at the intersection of US and global public health, they said in an article posted on the website of Foreign Policy magazine Tuesday.

"It is naive to think that the essential functions of the WHO could be recreated through bilateral accords — indeed, the long history of failure in state relations on health is proof positive. Trying to do so, and failing, is the last thing the world needs in the middle of a global pandemic," they wrote.