Donald Trump, as the number of US coronavirus cases approached 550 and deaths rose to 22, spent Monday morning again downplaying the threat to most Americans and lashing out at his political foes.

"The Obama/Biden Administration is the most corrupt Administration in the history of our Country!" the president tweeted with no supporting data or additional allegations.

But in the past, he has accused it of "spying" on his 2016 campaign and launching a baseless investigation of Russian election meddling that became the one eventually led by then-Special Counsel Robert S. Mueller III that he still calls a "hoax" and "witch hunt."

He fired off another tweet claiming there are "some very bad, sick people in our government" that are part of a "deep state" hellbent on taking him down, appearing to respond to a segment on MSNBC, a news network he claims to not watch, alleging it has a left-leaning bias.

"Trump has outmastered the Deep State. He's light years ahead of us." MSDNC. I disagree. We have a long way to go. There are still some very bad, sick people in our government - people who do not love our Country (In fact, they hate our Country!)." the president tweeted.

As Dr Anthony Fauci, the leading expert on infections, was on CNN urging elderly people to avoid cruise ships and possibly air travel, the president seemed mostly focused on his own re-election prospects. He tried sowing more bad blood within the Democratic ranks rather than offer any advice about the coronavirus or calm any nervous citizens or companies - or US stock markets.

"Now the Democrats are trying to smear Bernie with Russia, Russia, Russia. They are driving him Crazy!", Mr Trump tweeted, even though he himself suggested Mr Sanders was a Soviet- sympathising 'communist' and reported he went on his honeymoon decades ago in Moscow.

And as Fauci was talking about testing kits, his boss was focused exclusively on the politics of the crisis.