Walter Reed Medical Center

President Trump had been at Walter Reed since Friday evening for coronavirus treatment. In a tweet, he said, "Don't be afraid of Covid." The White House physician would not comment on the remarks.

The president's doctor has offered a fairly upbeat assessment of Trump's condition. But typically, only hospitalized COVID-19 patients in need of oxygen are given the drug.

A masked president waved to supporters from a black SUV, with Secret Service personnel in the vehicle wearing personal protective equipment to protect themselves from exposure to the president.

President Trump has experienced two drops in his oxygen levels over the course of his COVID-19 diagnosis, his medical team said Sunday, but that he "has continued to improve."