US President Donald Trump wears a mask as he visits Walter Reed National Military Medical Center in Bethesda, Maryland on Saturday. Photo: AFP

US President Donald Trump finally yielded to pressure and wore a face mask in public for the first time on Saturday as the US posted another daily record for coronavirus cases, while Disney World reopened in a state hit hard by the pandemic.

White House experts leading the national fight against the contagion have recommended wearing face coverings in public to prevent transmission of the illness. 

But Trump had repeatedly avoided wearing a mask, even after staffers at the White House tested positive for the virus and as more aides have taken to wearing them.

Hours after the World Health Organization urged countries to step up control measures to rein in the disease, Trump donned a dark mask bearing the presidential seal as he visited wounded military veterans at the Walter Reed military hospital in a suburb outside Washington DC.

"I've never been against masks but I do believe they have a time and a place," he told reporters.

Trump is trailing Democrat Joe Biden in the polls ahead of the November election and surveys show most Americans are unhappy with how he has handled the public health crisis. 

But the president has continued to praise his own response to the pandemic despite a cascade of figures showing the extent of the disease's spread across the US. 

The country posted yet another daily record of confirmed cases on Saturday night, with 66,528 new infections, while the death toll rose by almost 800 to nearly 135,000.

In Florida, where nearly one in six of those new infections were recorded, the Walt Disney World theme park partially reopened after four months of shutdown prompted by the virus. 

Hundreds of people queued to enter the park in Orlando, some sporting Mickey ears but all wearing face masks, with social distancing and other hygiene precautions also in place.

Days earlier, top US infectious disease expert Anthony Fauci said that Florida had begun reopening before meeting the criteria that would have enabled it to do so safely.

The coronavirus pandemic has infected nearly 13 million people, killed over 560,000 and triggered massive economic damage so far.

The US is the country worst hit by the illness, followed by Brazil - which surpassed 71,000 deaths on Saturday.

AFP