Donald Trump, amid governors' worries their states lack ample coronavirus tests, said he took his third on Thursday "out of curiosity."

The president has no hit for the Covid-19 hat trick, testing negative three times.

He admitted he took his first, during a time his team admitted the United States lacked tests in hard-hit states, because the media kept asking him if he had been tested after coming in contact with a Brazilian official who later tested positive.

This time, however, he appears to taken a test for his own amusement -- to see if it was more comfortable than the invasive initial test kit.

The president told Thursday afternoon's White House briefing on the coronavirus pandemic: "I just took it this morning. It took me literally a minute to take it. And it took me, I guess it was 14 or 15 minutes – I went to work, I didn't wait for it –but they said it took 14 minutes or something to come up with the conclusion.

"And it said the president tested negative for Covid-19. So that's the second one. I think I took it really out of curiosity to see how quickly it worked and fast it worked. I've done them both. And the second one is much more pleasant ... I can tell you that."

In a statement the White House physician, Sean Conley, said: "This morning, the president was tested again for Covid-19, utilising a new, rapid point-of-care test capability.

"He is healthy and without symptoms. Sample collection took just one minute, and results were reported back in 15 minutes. The president tested negative for Covid-19."