WILMINGTON, Del. - U.S. President-elect Joe Biden will give a speech on Wednesday highlighting the challenges facing Americans as the Thanksgiving holiday approaches and the nation faces a surge in coronavirus infections and a wave of unpopular health restrictions.

The address is meant to encourage Americans and focus on the sacrifices they are making during the holiday season, his office said, as officials across the country plead with Americans to stay at home and avoid large gatherings that can spread COVID-19.

Biden, who introduced his foreign policy and national security team on Tuesday as he begins a formal transition to the White House after defeating Republican President Donald Trump, has promised to make fighting the pandemic his top priority in office.

The number of patients being treated for coronavirus infections in U.S. hospitals surpassed 86,000, an all-time high, on Tuesday. The death toll has passed 257,000.

The soaring caseload has taxed healthcare providers and further strained medical resources as 171,000 Americans test positive and another 1,500 or more perish from COVID-19 every day, on average.

Not everyone appears to be heeding the warnings against travel. Millions of Americans have flocked to airports and highways in the days leading to Thursday's Thanksgiving holiday, leading to the busiest U.S. travel period since the early days of the pandemic in March, though well before pre-pandemic holiday levels.

Biden, who plans to spend Thanksgiving at home in Delaware with a few family members, said on Tuesday his team has been able to coordinate with the Trump administration on the pandemic, vaccine distribution plans and national security since getting the green light on Monday for formal transition efforts.

The White House also gave the go-ahead for Biden to start receiving the president's daily intelligence briefing.

"It's been offered," Biden told reporters on Tuesday. "I did not have it today. We're going to do it on a regular basis."

Trump has waged a failing legal battle to overturn the election results, falsely claiming it was stolen through widespread voting fraud. Critics have said Trump's refusal to accept the results undercut Biden's ability to combat the coronavirus pandemic and deal with national security threats.

BIDEN BUILDS CABINET

Biden has moved swiftly to fill some top jobs in his administration. In introducing his foreign policy team, he signaled he intended after taking office on Jan. 20 to steer the United States away from the unilateralist nationalism pursued by Trump and work together with the nation's allies.

He said the team, which includes trusted aide Antony Blinken as his nominee for U.S. secretary of state, would shed "old thinking and unchanged habits" in its approach to foreign relations.

"It's a team that reflects the fact that America is back, ready to lead the world, not retreat from it, once again sit at the head of the table, ready to confront our adversaries and not reject our allies, ready to stand up for our values," Biden said at a news briefing in Wilmington, Delaware. 

Biden also signaled that two former, more liberal, rivals for the Democratic presidential nomination, Senators Bernie Sanders and Elizabeth Warren, were not under consideration for Cabinet appointments, saying he needed their votes in the closely divided Senate.

Asked by NBC News about possibly nominating Sanders or Warren to his Cabinet, Biden said nothing was off the table but signaled they might be more needed in the Senate, where the party in power will govern by a razor-thin margin.

Two runoffs in Georgia on Jan. 5 will determine which party has a Senate majority. Democrats also saw their majority in the House of Representatives narrow in the Nov. 3 election.

"Taking someone out of the Senate, taking someone out of the House, particularly a person of consequence, is really a difficult decision," Biden said. "I have a very ambitious, very progressive agenda, and it's going to take really strong leaders in the House and Senate to get it done."

Trump has told allies he plans to pardon his former national security adviser Michael Flynn, who had pleaded guilty to lying to the FBI during the investigation into Russian meddling in the 2016 presidential election, a source familiar with the situation said on Tuesday.

The source said Trump could still change his mind on the planned pardon, which was first reported by Axios.

(Additional reporting by John Whitesides, Michael Martina, Susan Heavey; Editing by Scott Malone and Raju Gopalakrishnan) ((John.Whitesides@thomsonreuters.com; 202-898-8300; Reuters Messaging: john.whitesides@thomsonreuters.com))