President Donald Trump dismissed a mask-wearing reporter as being "politically correct" on Tuesday while the presumptive Democratic presidential nominee, Joe Biden, called him a "fool" for mocking their use.

The president's refusal to wear a face mask in public, defying recommendations from public health experts, has become a symbol for his supporters resisting stay-home orders amid the coronavirus crisis. To wear one then is seen by some as being anti-Trump.

As the United States nears its 100,000th death from the coronavirus and states grapple with how to reopen without putting lives at risk, wearing a mask to slow the spread of the disease has become the latest casualty of Trump-era partisanship.

Trump denied that he had been criticizing Biden's decision to wear a face covering for a public Memorial Day ceremony even though he retweeted a Fox News commentator mocking Biden's look of a black mask and dark aviator sunglasses mostly obscuring his face.

"Joe Biden can wear a mask, but he was standing outside with his wife, perfect conditions, perfect weather. . . . And so I thought it was very unusual that he had one on," Trump said during a news conference in the Rose Garden. "But I thought that was fine. I wasn't criticizing at all. Why would I ever do a thing like that?"

A moment later, the president told a reporter to remove his face mask while asking a question. The reporter offered to speak louder instead.

"Oh OK, you want to be politically correct," Trump said.

In contrast to Biden's full face covering, the president was barefaced at the Memorial Day remembrances he attended. Biden accused him of "stoking deaths" and said setting an example by wearing a mask "projects leadership."

“He’s a fool, an absolute fool to talk that way,” Biden said in a CNN interview. “Presidents are supposed to lead, not engage in folly and be falsely masculine.”