The president's comments at a campaign rally in Tulsa, Oklahoma, on Saturday brought quick rebukes from the campaign of likely Democratic presidential nominee Joe Biden as well as scores of Democratic lawmakers.

In an interview with Scripps for its local TV stations, Trump was asked Monday whether he did indeed tell aides to "slow it down". He did not directly answer the question.

"If it did slow down, frankly, I think we're way ahead of ourselves, if you want to know the truth," Trump said.

"We've done too good a job," adding that the reason the United States has more coronavirus cases is that it does more testing.

White House press secretary Kayleigh McEnany said any suggestion that testing has been curtailed is not rooted in fact, saying Trump made the slow-it-down comment "in jest".

She said that Trump's comments were an effort to criticise the media for its coverage of the coronavirus and its "failure" to understand that "when you test more, you also find more cases".

However, the US is seeing disturbing trends in several benchmarks, including the percentage of tests that prove positive for the virus.

Health officials say that testing in the United States early on was insufficient for optimal containment.

In early March, Dr Anthony Fauci, a member of the White House coronavirus task force, testified that the nation's testing system was "not really geared to what we need right now" and added: "It is a failing. Let's admit it."

But now, about a half-million people per day are being tested, and the president and his aides have been repeatedly touting the United States as leading the world in testing.

The United States has confirmed nearly 2.3 million COVID-19 cases, which represents about a quarter of the world's cases.

More than 120,000 people in the US with COVID-19 have died. The next closest nation is Brazil, with 50,600 deaths.

Australian Associated Press