Bill and Melinda Gates tell David Muir Trump's halting WHO funding 'just doesn't make any sense' Their foundation is giving additional funding to battle COVID-19.

In an exclusive interview, Bill Gates told ABC News anchor David Muir that he did not agree with President Trump's move to halt U.S. funding to the World Health Organization.

"I'm hopeful that he doesn't follow through on that because we need their support. This is a global problem. They are the institution that, you know, brings nations together and make sure that, you know, that were sharing best practices between all of those countries," said Gates, who spoke to Muir along with wife Melinda Gates on Wednesday.

"There'll be plenty of time to look back and see which countries did things well, which didn’t, where should WHO have done things differently, but we're very supportive of the role WHO plays," Gates said. "You know, they're the ones who helped eradicate smallpox. They, you know, see what's going on globally. And so I hope that doesn't actually happen."

On Tuesday, Trump said he was halting funding to the World Health Organization and accused the United Nations agency of "severely mismanaging and covering up the spread of the novel coronavirus" by "parrot(ing)" Chinese government data and not "call(ing) out China's lack of transparency."

His decision has been criticized by lawmakers who challenge its legality, public health experts who say it undermines the global fight against COVID-19, critics who argue Trump is searching for a scapegoat after he was slow to act and similarly praised China's initial response, and even the U.S. Chamber of Commerce, a conservative business lobby, which said the timing is wrong.

Bill Gates said that he and Melinda Gates had tweeted their support for the WHO.

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"I think it's worth saying, we've been working with the WHO for over 20 years as a foundation. And no institution is perfect, but it's the global response that's going to get us through this, and WHO was created after World War II to deal with exactly these kinds of issues around the world. So halting funding right now, that just doesn't make any sense," Melinda Gates told Muir, the anchor of "World News Tonight."

On Wednesday, the Gates Foundation announced that it would be expanding its funding for the global response to COVID-19 with an additional $150 million of grant funding, raising the foundation's commitment to fighting the pandemic to more than $250 million.

"This new $150 million that we are announcing is really to help low- and middle-income countries, because we're watching the spread of the disease around the world," Melinda Gates told Muir. "We need to shore up their health system so they have the protective gear for their health care workers."

According to the news release, funding was also intended to "support development of diagnostics, therapeutics, and vaccines; help strengthen African and South Asian health systems; and help mitigate the social and economic impacts of the virus."

The foundation said it was calling on "world leaders to unite in a global response to COVID-19 to ensure equitable access to diagnostics, treatments and vaccines" and that it would work with national governments and groups like WHO, UNICEF and the Global Fund to Fight AIDS, Tuberculosis and Malaria.

Melinda Gates said that there was still a lot of science that researchers around the world needed to do, but that Americans could do their part in fighting the virus and its spread by protecting the most vulnerable at this time.

"Our health is our most important thing. ... We have to protect our health while we slowly go back to the economic opportunities that we all have, and we're going to have to take care of families who, you know, their business has gone under, they've lost their job, or they’re still struggling to put a meal on the table after the economy starts to slowly open up," Melinda Gates said.