Trump tweets picture of himself wearing 'patriotic' mask in gloating message as US coronavirus death toll hits 140,000

President suggests Americans wear masks nearly four months after CDC recommendations

After weeks of refusing to wear a face covering in public, Donald Trump has posted to Twitter a black-and-white photo of himself wearing a mask and encouraged Americans to do the same as the nation's coronavirus death toll tops more than 140,000.

The president – calling Covid-19 "the Invisible China Virus" – said that "many people say that it is Patriotic to wear a face mask when you can't socially distance."

"There is nobody more Patriotic than me, your favorite President!" he added.

His message appeared hours after US Surgeon General Jerome Adams's appearance on Fox News, in which he pleaded with Americans to wear masks in public as infections surge across the US, topping more than 3.7 million, with 1 million new cases within the last month alone.

The president has resisted calls from health officials and medical experts urging Americans to wear face masks in public when unable to adequately remain physically distant from others.

On 3 April, following new guidance from federal health officials, the president – unprompted – said: "I don't think I'll be doing it."

He said: "It's only a recommendation ... I'm choosing not to do it."

In May, the president refused to wear a mask inside a Honeywell facility that manufactured masks despite warnings posted onsite telling workers and visitors to do so.

Vice President Mike Pence also has been criticised for failing to wear a mask inside the Mayo Clinic in Minnesota.

The president was photographed wearing a mask for the first time during a visit with administration staff to Walter Reed hospital on 11 July.

He wore a mask during a visit to a Ford factory in May, though he told reporters he "didn't want to give the press the pleasure of seeing it."

"Cloth face coverings are recommended as a simple barrier to help prevent respiratory droplets from travelling into the air and onto other people when the person wearing the cloth face covering coughs, sneezes, talks, or raises their voice," according to recommendations from the Centres for Disease Control and Prevention. "This is called source control. This recommendation is based on what we know about the role respiratory droplets play in the spread of the virus that causes Covid-19, paired with emerging evidence from clinical and laboratory studies that shows cloth face coverings reduce the spray of droplets when worn over the nose and mouth."

CDC Director Robert Redfield also has suggested that the virus could be adequately controlled within "four to eight weeks" if everyone in the US wore masks.

As infections began to spread within the last several weeks, state officials once reluctant to impose stringent quarantine efforts or mask mandates began ordering residents to wear them in public, pointing to their ability to minimise the risk of transmission.

But the president has been reluctant to follow the same measures or issue a message to Americans to follow the CDC's guidelines, suggesting instead that wearing masks is a politically correct gesture.

The issue has become a political one, seen among many of the president's supporters as a suppression of civil liberties.

In May, the president mocked his Democratic rival Joe Biden for wearing a mask by retweeting a post from Fox News political analyst Brit Hume sharing a photograph of the former vice president wearing sunglasses and a black mask on Memorial Day.

"This might help explain why Trump doesn't like to wear a mask in public," Mr Hume wrote.

Mr Biden wore the mask during a visit to the Delaware Memorial Bridge in Wilmington.