US President Trump said from his hospital room that the next few days will be the real test of his treatment for COVID-19, capping a day of contradictory messages from the White House about his condition.

Iran PressAmerica: In a four-minute video posted on Twitter, Trump, looking tired and wearing a jacket and open-necked shirt, said he "wasn't feeling so well" when he first arrived at Walter Reed National Military Medical Center on Friday.

"Over the next period of a few days, I guess that's the real test, so we'll be seeing what happens over those next couple of days," Trump said.

The remarks came hours after differing assessments of his health from administration officials left it unclear how ill the president had become since he tested positive for COVID-19 on Thursday night, a matter of enormous public concern.

The US President Donald Trump is free of fever and improving after being hospitalized with COVID-19 but is not yet out of danger, his physician, Dr. Sean Conley said.

"He spent much of the afternoon conducting business, and has been up and moving about the medical suite without difficulty," Conley said late on Saturday in a statement.