U.S. President Donald Trump put on a face mask Saturday for his visit with American service members at a military hospital outside Washington.Trump, who has mostly avoided wearing a mask in public, said he would wear one during his visit to Walter Reed National Military Medical Center in Bethesda, Maryland, telling Fox News “it’s a very appropriate thing” to do in a hospital setting.The president said that in addition to meeting with wounded soldiers, he would meet with workers tasked with containing the spread of the new coronavirus.Trump has been criticized for not wearing a mask or promoting the use of them, even within his Republican Party in recent weeks.His visit with the troops and employees comes amid surges of COVID-19 cases in the U.S., which continues to lead the world in both infections and fatalities.More than 3.2 million people in the U.S. were infected with the virus as of Saturday, about one-quarter of the almost 12.6 million cases worldwide, according to Johns Hopkins University statistics.The more than 134,000 deaths in the U.S. represent over one-fourth of the nearly 562,000 COVID-19 fatalities throughout the world.Trump last visited Walter Reed in November 2019. The visit was unscheduled and secretive, and was described by the White House as an “interim checkup” nine months after his previous medical examination.The White House dismissed speculation about any “urgent or acute” issues involving Trump’s health.