Biden urges safe Thanksgiving amid pandemic; Trump pardons ex-aide Flynn

President-elect Joe Biden pleaded with Americans to take steps to remain safe over the Thanksgiving holiday as COVID-19 cases soar.

Biden gave a presidential-style speech acknowledging people's fatigue with restrictions amid the coronavirus pandemic, but urged them to exercise caution as caseloads surge.

"I know the country has grown weary of the fight. We need to remember - we're at war with the virus, not with one another," Biden said as he urged Americans to forgo the type of big family gatherings normally associated with Thursday's holiday, wear protective masks and maintain social distancing.

The Democratic former vice president again said he would take immediate steps to address the coronavirus pandemic when he takes office on January 20. During the campaign, Biden accused President Donald Trump, a Republican, of panicking and surrendering in the face of a public health crisis.

Shortly after Biden spoke, Trump pardoned his former national security adviser Michael Flynn, who had pleaded guilty to lying to the FBI about his contacts with the former Russian ambassador in Washington.

It marked the latest instance in which Trump has used his power of executive clemency to benefit a friend or associate.

Prominent Democrats responded quickly and angrily.

"President Trump’s pardoning of Michael Flynn, who twice pleaded guilty to lying to the FBI about his dealings with a foreign adversary, is an act of grave corruption and a brazen abuse of power," House of Representatives Speaker Nancy Pelosi said in a statement.

More than 261,000 Americans have died from COVID-19, with the daily toll on Tuesday surpassing 2,000 for the first time since May, as infections and hospitalisations surge nationally. The United States leads the world in COVID-19 cases and deaths.

Biden said the US faced "a long hard winter" but that it was during the most difficult circumstances that "the soul of our nation has been forged."

He said he hoped the recent positive news on vaccine development - the first shots potentially could be made available to some Americans within weeks - would serve as an incentive for people to take simple steps to get the virus under control.

Since winning the November 3 election, Biden has offered a message of healing and reconciliation after Trump's tumultuous term, while the president still refuses to concede and falsely claimed again on Wednesday that Biden's victory was stolen.

Without mentioning Trump, Biden addressed the messy aftermath of the vote.

"Our democracy was tested this year," Biden said. "In America, we have full and fair and free elections and then we honor the results. The people of this nation and the laws of the land won't stand for anything else."