President Donald Trump arrived Friday evening at Walter Reed National Military Medical Center in Bethesda, Maryland, where he will stay and work out of an office for the next few days.

The White House said the decision to remain in the hospital for a few days was "out of an abundance of caution."

Trump walked on his own to his waiting helicopter and displayed no major signs of illness. It was the first time he went out of the White House residence since announcing 16 hours later that he tested positive for COVID-19.

Trump waved to the media and gave a thumbs up. But he did not stop to talk. He was wearing a navy-blue suit, a blue silk necktie, and a dark face mask.

Chief of staff Mark Meadows followed him aboard. Meadows was also seen wearing a mask. Trump arrived at the medical facility a little later. The first lady is not accompanying the President to the hospital.

Trump has posted an 18-second video to his Twitter account. He reassured the American public that he is doing well after receiving a positive COVID-19 diagnosis.

"I want to thank everybody for the tremendous support. I'm going to Walter Reed Hospital. I think I'm doing very well. We're going to make sure that things work out. The first lady is doing very well. So thank you very much, I appreciate it. I will never forget it. Thank you," he noted.

Reports said it is extremely rare for a president to spend days in a hospital with the extensive medical facilities available at the White House.

A source said that Trump was spooked after he tested positive for coronavirus. He has become increasingly alarmed by his diagnosis. Trump was reported to develop a low-grade fever and had it since Friday morning.

White House officials said there is a reason for concern about the 74-year-old President's health. A top administration official noted that Trump is well for now, but they fear that things can change quickly.

One source added that the President's condition is worse than first lady Melania Trump, who also tested positive for COVID-19.

White House spokeswoman Alyssa Farah noted that there had been no transfer of power to Vice President Mike Pence. Farah said that the President is still in charge.

The White House maintained that Trump remains in good spirits, adding that he has mild symptoms and has been working throughout the day.

Press secretary Kayleigh McEnany said the President would be working from the presidential officer at Walter Reed for the next few days out of caution and at the recommendation of his physician and medical experts.

McEnancy added that Trump appreciates the support for both of him and the first lady.

Pence remains in good health and was working from his residence at the Naval Observatory, according to an administration official.

Trump's physician Dr. Sean Conley said in a memo shared by White House officials that Trump has "received a single 8 gram dose of Regeneron's polyclonal antibody cocktail" as a precautionary measure.

Conley said that Trump "completed the infusion without incident." He further noted that a team of experts is evaluating the President and they will be making recommendations to the President and the first lady in regards to the next best steps.

Aside from Regeneron, Conley added that Trump has also been taking zinc, vitamin D, famotidine, melatonin, and daily aspirin.

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