US President Donald Trump has worn a mask during a visit to a military hospital, the first time he’s been seen in public with the type of facial covering recommended by health officials as a precaution against spreading coronavirus.

Trump flew by helicopter on Saturday to Walter Reed National Military Medical Center in suburban Washington to meet wounded servicemembers and health care providers caring for COVID-19 patients.

As he left the White House, he told reporters: “When you’re in a hospital, especially … I think it’s expected to wear a mask.”

Trump was wearing a mask in Walter Reed’s hallway as he began his visit. He was not wearing one when he stepped off the helicopter at the facility.

The president was a latecomer to wearing a mask during the pandemic, which has raged across the US since March and infected more than 3.2 million and killed at least 134,000.

Most prominent Republicans, including Vice-President Mike Pence, endorsed wearing masks as the coronavirus gained ground this summer.

The wearing of masks became another political dividing line, with Republicans more resistant to wearing them than Democrats. Few masks were seen at recent rump campaign events in Tulsa, Oklahoma, Phoenix and South Dakota’s Mount Rushmore.

The only time Trump has been known to wear a mask was during a private part of a tour of a Ford plant in Michigan.

-AAP