WASHINGTON, April 15 (Xinhua) -- U.S. President Donald Trump faced intense blowback on Wednesday due to his decision to withhold the nation's funding to the World Health Organization (WHO) in the middle of the global COVID-19 pandemic.

House Speaker Nancy Pelosi, the top Democrat in the U.S. Congress, called the decision "senseless," as the WHO leads the global fight against the coronavirus pandemic.

"We can only be successful in defeating this global pandemic through a coordinated international response with respect for science and data," Pelosi said in a statement.

While saying the decision is "dangerous" and "illegal," the speaker vowed that it "will be swiftly challenged."

Lawrence Gostin, director of the O'Neill Institute for National and Global Health Law at Washington D.C.-based Georgetown University, tweeted on Wednesday that in the United States, Congress "appropriates funds for special purposes" and the "executive branch is usually required to expend funds."

"But Trump could delay & disrupt. His refusal to fund would raise major ethical/legal implications -- grounds for investigation & oversight," he warned.

During a press conference at the White House on Tuesday announcing the move, Trump claimed that the "WHO failed to adequately obtain and share information in a timely and transparent fashion," adding that a review is being conducted.

On Wednesday, he doubled down on his criticism of the Geneva-based UN specialized agency, accusing it, without providing any evidence, of what he has alleged as cover-up and mismanagement of the coronavirus outbreak.

The remarks came as the Trump administration is aggressively defending its handling of the crisis in the United States after it has been scrutinized for downplaying the threat from the coronavirus early on and faulted for delays in testing.

The virus has caused at least 637,000 infections and more than 30,000 deaths in the United States, both the highest on record.

U.S. lawmakers and health experts have said the White House is scapegoating the WHO in the hope of distracting the public from its own failures in responding to the pandemic.

"The WHO had produced 1.4 million tests by the end of February," Chris Murphy, U.S. senator from Connecticut, tweeted on Wednesday. "We took none of them, because Trump decided to produce his own test, then botched the development and roll out."

"It wasn't the WHO that put us in the position we are today. It was our own President," Murphy added.

Gostin, in other tweets on Wednesday, said pulling funds from the WHO "would be disastrous."

"Poor countries about to hit #COVID19 peaks rely on WHO for resources and expertise," the professor wrote. "Without more funds, many more will die. It will also blow back onto the US."

Microsoft co-founder Bill Gates tweeted on Wednesday that halting funding for the WHO during a world health crisis is "as dangerous as it sounds."

"Their work is slowing the spread of COVID-19 and if that work is stopped no other organization can replace them. The world needs @WHO now more than ever," the philanthropist stressed.

According to a new tally from Johns Hopkins University on Wednesday night, the number of confirmed COVID-19 cases worldwide has topped 2 million, with more than 136,000 deaths.

WHO Director-General Tedros Adhanom Ghebreyesus tweeted on Wednesday that the coronavirus doesn't discriminate between rich and poor or large and small nations, regardless of people's nationalities, ethnicities, or ideologies.

"This is a time for all of us to be united in our common struggle against a common threat -- a dangerous enemy," he said. "We will continue to work with every country and every partner, to serve the people of the world, with a relentless commitment to science, solutions and solidarity."

Besides, the director said the WHO's performance in tackling the pandemic will be reviewed by its members and independent bodies in due course.

"This is part of the usual process to ensure transparency, accountability and recommendations for future outbreak responses," he added.