US President Donald Trump waves to supporters as he briefly rides by in the presidential motorcade in front of Walter Reed National Military Medical Center, where he is being treated for COVID-19 in Bethesda, Maryland, US, October 4, 2020. (Photo: REUTERS)

Mr. Trump wore a mask as he waved from the back seat of a black SUV in front of the Walter Reed National Military Medical Center outside Washington.

It was his first appearance in public since he was evacuated to the hospital on Friday. Doctors said the president was improving, although they were monitoring the condition of his lungs after he received supplemental oxygen. They said he could be sent back to the White House as soon as Monday.

Stock markets rose on Monday on hopes that President Trump could be discharged from hospital later in the day, easing some of the political uncertainty that shook global bourses in the previous session.