"In fact, we will be doing more testing" instead of less, he said.
The US has been hit harder than any country in the world, with more than 120,000 deaths, new outbreaks reaching alarming levels across several states, and a government showing little ability to stem the spread.
Fauci, the government's top infectious disease expert, led a witness panel that stressed it was difficult to predict how long coronavirus will remain a threat.
"While it remains unclear how long the pandemic will last, COVID-19 activity will likely continue for some time," the experts said in prepared testimony attributed to all of them, inducing Fauci and Centers for Disease Control and Prevention (CDC) director Robert Redfield.
"These challenges are many, and they are historic," they said.
Fauci also said he feels "cautiously optimistic" about the pace of vaccine testing and reiterated his hope that broad production and use of a coronavirus vaccine could come by "the end of this calendar year" or early 2021.
The CDC's Redfield made clear in the House Energy and Commerce Committee hearing that boosting testing was critical to bringing the virus under control.
But the testimony came as Trump faced criticism for telling a Saturday campaign rally -- where most attendees did not wear masks, against CDC recommendations -- that he wanted to actually slow coronavirus testing.
- 'I don't kid' -
White House aides said the president's remarks were tongue in cheek, but on Tuesday Trump doubled down.
"I don't kid," he told reporters before praising the US testing scheme, which Trump said has tested 25 million people, as the best in the world.
"By having more tests, we find more cases," Trump said, even suggesting the high number is a political liability for him during an election year.
"By having more cases, it sounds bad," he said. "But actually what it is, is we're finding people."
Trump has repeatedly lashed out at criticism of his handling of the pandemic, and on Tuesday he remained defiant that his early action -- including banning flights from China, where the virus first emerged, in late January -- helped prevent a catastrophe.
"We did a great job on CoronaVirus," Trump tweeted. "We saved millions of US lives!"
Energy committee chairman Frank Pallone, opening the hearing, blasted as "extremely reckless" Trump's suggestion that he wants fewer tests.
"Trump refuses to even acknowledge the problems we face," Pallone said.
While former epicenters New York and New Jersey have largely controlled their outbreaks, the virus is now increasing in 20 states including Florida, Texas and Arizona.
Florida is a potential new coronavirus hotspot that surpassed 100,000 cases on Monday, according to local health officials.
Brett Giroir, the administration's testing coordinator, told the panel he expects the country will be able to test 40-50 million people per month by autumn.
The inability to suppress the new case trend nationwide also raises the specter of a "second wave," a scenario that some health experts warn could be compounded in the autumn and winter, the typical American flu season.
Redfield, who described the coronavirus as the health challenge of the century, said the CDC was working on a vaccine that would test for influenza and COVID-19 at the same time.
© 2020 AFP
