US President Donald Trump told reporters Thursday that he had taken a second test for the COVID-19 novel coronavirus "out of curiosity." He indicated his results were negative.

"I did take a test that just came out ... I just took it this morning and I took it, it took me literally a minute to take it," Trump told reporters at the White House on Thursday. "They said it took 14 minutes or something to come up with a 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, how fast it worked, and it's a lot easier. I've done them both, and the second one is much more pleasant," Trump said.

Copies of this were just distributed to the WH briefing room right before Trump took to the mic pic.twitter.com/9HkuknZcHg — Asawin Suebsaeng (@swin24) April 2, 2020

​However, the US Centers for Disease Control and Prevention have cautioned that a negative test does not mean you cannot get the disease later, or even that you don't already have the disease, but it's still in its early stages.

"If you test negative for COVID-19, you probably were not infected at the time your specimen was collected. However, that does not mean you will not get sick. It is possible that you were very early in your infection at the time of your specimen collection and that you could test positive later, or you could be exposed later and then develop illness. In other words, a negative test result does not rule out getting sick later," the CDC says on its website.

The Food and Drug Administration (FDA) recently approved the new test, which is being rolled out across the country. Both kinds of tests use polymerase chain reaction (PCR) testing, which checks samples swabbed from the nose and throat for the virus.

Trump was previously tested on March 14, following a back-and-forth with reporters about whether he needed the test after a Brazilian official with whom he had been photographed was diagnosed with the novel coronavirus.

At least two other heads of government, British Prime Minister Boris Johnson and Prince Albert of Monaco, have tested positive for COVID-19, and Brazilian President Jair Bolsonaro has had multiple scares with the virus, but has not yet been verified to have the illness.