America’s top infectious disease expert has told lawmakers that the nation is seeing a “disturbing surge” in coronavirus infections in some states.
A panel of health officials, including Dr Anthony Fauci, said the next few days will be crucial to stem the new outbreaks.
Cases are climbing rapidly across a number of US states.
Four top experts also testified they were never told by President Donald Trump to “slow down” testing.
Their comments come after Mr Trump told a weekend rally in Oklahoma that he had asked his team to do less testing to help keep official case counts down,.
The White House has said his comment was “in jest”.
“To my knowledge, none of us have ever been told to slow down on testing,” Dr Fauci, the director of the National Institute of Allergy and Infectious Disease, testified to a congressional committee investigating the US response to the pandemic.
“In fact, we will be doing more testing,” he added.
The other three officials – representing the Centers for Disease Control and Prevention (CDC), the Food and Drug Administration (FDA) and the Department of Health and Human Service – also disputing Mr Trump’s comment, saying they had never been directed to slow testing.
More than 120,000 Americans have died from the coronavirus – more than any other nation.
What else did experts say?
Dr Fauci warned of “a disturbing surge of infection” and “increased community spread” in many southern and western states.
“A couple of days ago there were 30,000 new infections”, in a single day, he said. “That’s very troubling to me.”
“The next couple of weeks are going to be critical to address those surges that were seeing Texas, Florida, Arizona, and other states.”
CDC Director Dr Robert Redfield called testing “a critical underpinning of our response” but said social distancing measures are more important ways to keep the virus from spreading.
Dr Redfield also called on all Americans to get a flu jab this year, saying the public must “embrace flu vaccinations with confidence”.
“This single act will save lives,” he added.
Dr Fauci added that he is “cautiously optimistic” a vaccine may be ready by the end of 2020.
He said it is a matter of “when and not if” the vaccine is ready, but added that it “might take some time”.
Drug company Moderna has plans “to launch a Phase 3 clinical trial as early as July 2020, pending positive results from this Phase 2 trial,” he said.