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Joe Biden on Thursday called for an immediate nationwide mask mandate for the next three months.

"Every American should be wearing a mask when they're outside for the next three months at a minimum," Biden told reporters in Wilmington, Delaware, after he and his running mate, Sen. Kamala Harris, left their Covid-19 briefing with health experts.

Both Biden and Harris emerged from their briefing wearing black face masks.

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Biden said he would mandate face masks nationwide if he was president. He cited health experts who predict a nationwide mask mandate would save 40,000 lives during the Covid-19 pandemic.

The Democratic nominee called on every governor to mandate face masks until the November election. "Let's institute a mask mandate nationwide, starting immediately and we will save lives," he said.

He urged Americans to "be a patriot" and wear the masks.

Biden said he hoped President Donald Trump "learned the lesson" but he added a mask mandate is not about politics.

Some pundits believe Biden called for mandatory face masks until the election to boost mail-in voting.

But Dr. Anthony Fauci backed President Trump's demands for in-person voting, saying, "there is no reason we can't have in-person voting."

Fauci said voting at polling stations is okay if guidelines are observed.

Meanwhile, Georgia Gov. Brian Kemp dropped his lawsuit against Atlanta Mayor Keisha Lance Bottoms, saying he would address the issue of mandatory face masks in his next executive order.

Kemp sued Bottoms in federal court after she mandated face masks in the city of Atlanta.

"Unfortunately, the mayor has made it clear that she will not agree to a settlement that safeguards the rights of private property owners in Georgia," Kemp said. "Given this stalemate in negotiations, we will address this issue in the next executive order. We will continue to protect the lives and livelihoods of all Georgians."