In a sombre speech from his base in Delaware, US President-elect Joe Biden pleaded with Americans on the eve of their Thanksgiving holiday to take steps to remain safe as COVID-19 cases surge and pledged again to make combating the pandemic a top priority when he takes office in January.
He urged people to forgo big family gatherings, wear protective masks and maintain social distancing.
"I know we can and we will beat this virus," Biden added, acknowledging that Americans are feeling pandemic fatigue. "Life is going to return to normal. I promise you. This will happen. This will not last forever."
The Democratic former vice-president has vowed to make tackling COVID-19 a top priority after taking office on January 20, having accused Trump during the campaign of panicking and surrendering in the face of a public health crisis.
"Looking back over our history, you see that it's been the most difficult circumstances that the soul of our nation has been forged. And now we find ourselves again facing a long hard winter," Biden said. "We are at war with the virus not with each other."
Public health officials have urged Americans to stay at home for Thursday's holiday and avoid large gatherings that could spread the pathogen. More than 260,000 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.
Millions of Americans have flocked to airports and highways, leading to the busiest U.S. travel period since the early days of the pandemic in March, though well below pre-pandemic holiday levels.
Aides said Biden and Vice-President-elect Kamala Harris planned to spend Thanksgiving with their families.
Trump phones in Gettysberg address
Trump cancelled a trip on the eve of Thanksgiving to accompany his personal lawyer, Rudy Giuliani, to a meeting of Republican state legislators in Gettysburg, where Giuliani repeated his unsubstantiated claims of voting fraud.
But Trump spoke to the participants by speaker phone, repeating his debunked claims that the election had been stolen, drawing cheers from the crowd.
"This election has to be turned around. This election was lost by the Democrats. They cheated. It was a fraudulent election," Trump said, without offering evidence.
In addition to beating Trump by 306-232 in the Electoral College - a margin that Trump called "a landslide" when it was his margin in 2016 - Biden won more than 80 million ballots in the popular vote, more than 6.1 million votes over Trump.
State and federal officials have repeatedly said there is no evidence of any large-scale fraud.
Gettysburg is best known as the site of a pivotal 1863 battle in the US Civil War and the famed Gettysburg Address in which President Abraham Lincoln vowed that "government of the people, by the people, for the people, shall not perish from the earth".
Chinese President Xi Jinping has congratulated Biden and expressed hope for "win-win co-operation" amid conflicts over trade, technology and security that have plunged Sino-American relations to their lowest level in decades.
Biden is widely expected to try to resume co-operation with China on North Korea, climate change and the coronavirus following the confrontational approach of President Donald Trump, who launched a tariff war and sanctioned Chinese companies. But analysts expect few major US policy changes due to widespread frustration with Beijing over trade, human rights and technology theft.
China became one of the last major governments to congratulate Biden two weeks ago, although Xi himself did not congratulate Biden at the time. There was no explanation for the delay but some commentators suggested Beijing wanted to avoid straining relations with Trump, who had yet to concede and is in office for another two months until January 20.
In a message to Biden on Wednesday, Xi said "healthy and stable" relations are "the common expectation of the international community," according to the official Xinhua News Agency.
"We hope the two sides will uphold the spirit of non-conflict and non-confrontation, mutual respect and win-win co-operation, will focus on co-operation, control differences and promote healthy and stable development of Chinese-US relations," the statement said.
During the election campaign, Biden vowed a tough line on China's expanding influence worldwide and called Xi a "thug" for his human rights practices. A Biden transition official said, "We appreciate the congratulations from all world leaders who have conveyed them, including President Xi."
The United States and China have one of the world's biggest trading relationships but official ties have been roiled by spying accusations, the coronavirus pandemic, Beijing's crackdown on Hong Kong and disputes over control of the South China Sea.
Trump has blocked access to US technology for Chinese telecom equipment maker Huawei Technologies on security grounds. He is trying to limit access to the United States for Chinese social media services such as TikTok, which the White House says might gather too much personal information about Americans.
Trump has stepped up pressure on Beijing since the election by issuing an order that bars Americans from investing in securities issued by companies US officials say are owned or controlled by the Chinese military.