Biden and Vice President-elect Kamala Harris are participating in a virtual briefing with expert members of their national security and foreign policy agency review teams from the Queen Theater in Wilmington, Delaware, and taking the opportunity to draw stark contrasts between Trump's "America First" policy and their incoming White House.

At the top of the briefing, Biden praised the team for their work despite delays in the transition prompted by the Trump administration refusing to recognize Biden's ascertainment as the president-elect for more than two weeks.

"You’ve done it all under incredibly difficult circumstances, dealing with the COVID protocols, delays, delays in the ascertainments, and in a few cases obstruction from the current leadership," Biden said, thanking the group before taking aim at Trump's "go-it-alone approach" of the past four years.

“The truth is, the challenges we face today can't be solved by any one country acting alone. They demand American leadership. They demand cooperation with our allies and our partners. So I’m looking forward to hearing your assessments about the greatest challenges we may inherit and as we restore the principle of American leadership on the global stage -- which we have to and will do," Biden added.

After the briefing, Biden is slated to deliver afternoon remarks on the group's findings.

-ABC News' Molly Nagle

Dr. Celine Gounder, a member of Biden’s COVID-19 task force, said Monday morning there is "no question" the country will see a post-holiday surge of coronavirus cases and, to help offset the worsening pandemic, confirmed Biden will invoke the Defense Production Act once in office to increase vaccine supply.

Gounder criticized the Trump administration for moving too slowly on vaccine distribution and said Biden will force manufacturers to step up by invoking the Defense Production Act, which gives the president the power to direct civilian businesses to help meet orders for products necessary for national defense.

“In the last two weeks, we basically averaged about a million doses of vaccine administered per week. We need to be getting to a million doses per day if we're going to reach the president-elect's target of 100 million doses in 100 days," Gounder said. She went on to explain that invoking the act is "to make sure that the personal protective equipment, the test capacity and the raw materials for the vaccines are produced in adequate supply so that those aren't limiting steps in all of this.”

Gounder also claimed the country will see "a major increase" in testing as well as in genetic surveillance to track new variants of the virus with the incoming administration.

-ABC News’ Brian Hartman

Trump is slated to return to Georgia in one week for a campaign rally on the eve of the Jan. 5 runoff races that are set to determine which party holds power in the U.S. Senate.

Sitting GOP Sens. Kelly Loeffler and David Perdue are facing off against Democratic contenders Rev. Raphael Warnock and Jon Ossoff, respectively, as early voting continues across the state Monday.

Earlier this month Trump stumped for Loeffler and Perdue at his first rally since the November election. There, he assaulted the integrity of Georgia's vote but encouraged GOP turnout in the wake of Biden becoming the first Democratic presidential candidate to win the state since 1992. Democrats are now hoping to cement its status as a swing state.

Biden, too, has stopped in Georgia since the presidential election to campaign for Warnock and Ossoff as the promise of passing the big ticket legislation he’s hoping for hangs on their races. If Democrats pick up both seats, Vice President-elect Kamala Harris will have the power to settle tie-breaker votes in Congress' upper chamber.

The Biden-Harris transition team has announced 12 new members of their incoming staff for the Office of Digital Strategy -- which the transition says will be a “robust” team in the Biden White House.

All 12 staffers announced Monday morning previously worked on the Biden-Harris campaign, which relied heavily on digital engagement amid the COVID-19 pandemic.

"With much of our lives online, it is critical for this administration’s digital efforts to be inclusive and extensive,” said Vice President-elect Kamala Harris in a joint statement announcing the picks.

-ABC News Molly Nagle

The House narrowly passed a bill that would increase the amount of money Americans receive in a second round of pandemic relief stimulus payments to $2,000, up from $600.

The final vote tally was 275-134, receiving the two-thirds majority it required under the expedited vote. There were 44 Republicans who voted with Democrats.

Even though Trump supports the measure, a number of Republicans voted against the bill. Its fate remains uncertain in the Senate.

The House vote comes one day after Trump signed the $2.3 trillion spending and COVID-19 relief bill, which included $600 stimulus checks for Americans who make $75,000 or less. Trump initially threatened to hold up the bill last week and said it was a "disgrace." He spent the next several days calling on Congress to pass a bill that included $2,000 stimulus checks instead.

Democrats took up Trump's offer last week and attempted to pass a bill that would send Americans $2,000 checks via unanimous consent but that attempt failed over Republican objections. House Speaker Nancy Pelosi vowed to bring the bill to the floor for a full recorded vote on Monday.

Even though the bill has now cleared the House, at this point it's unclear if the Republican-led Senate will bring the bill to the floor for a vote. Senate Majority Leader Mitch McConnell made no promises in his statement Sunday when he commended the president for finally signing the COVID-19 relief bill into law.

Pelosi called on Trump to put more pressure on his party to back the payments.

"Every Republican vote against this bill is a vote to deny the financial hardship that families face and to deny the American people the relief they need," she said in a statement released Sunday.

Senate Minority Leader Chuck Schumer said Sunday that he would try to pass the legislation in the Senate.

"No Democrats will object. Will Senate Republicans?" he tweeted.

-ABC News' Mariam Khan