President-elect Joe Biden will receive his first President's Daily Brief on Monday, his transition team said, after the General Services Administration formally ascertained Biden as the winner Monday evening.

The classified briefs contain sensitive national security information and are delivered by the Office of the Director of National Intelligence.

In a press briefing Wednesday, transition officials Jen Psaki and Kate Bedingfield said their agency review teams have met with more than 50 major agencies and commissions and held more than 30 virtual briefings in order to “establish a rhythm.”

BIDEN TO BEGIN RECEIVING PRESIDENT'S DAILY BRIEF, MET WITH AGENCIES AFTER ASCERTAINMENT

The meetings, according to Psaki, were focused on “critical policy areas,” including COVID-19, Operation Warp Speed, PPE supply chain, support for small and medium businesses, and housing evictions.

As for national security, Psaki said the team’s agency review was focused on “fact-finding,” and threats from both “terrorists and state actors who seek to exploit the transition process.”

“As you may have also heard, we are working with ODNI and the White House on the President’s Daily Brief (PDB),” Psaki said. “We expect the first briefing to take place on Monday.”

Psaki added that there will be “coordination” with national security and domestic teams “when working to address” and get the coronavirus pandemic “under control.”

GSA CHIEF INFORMS PRESIDENT-ELECT BIDEN THAT FORMAL TRANSITION PROCESS CAN BEGIN

“There is a coordination and a cohesion across domestic and international work,” Psaki said, calling it “essential and important as we look ahead.”

Meanwhile, Biden has already announced nominations for key Cabinet posts, including Antony Blinken as secretary of state, Alejandro Mayorkas as secretary of homeland security, and Avril Haines to serve as the first woman to lead the intelligence community, among other positions, with more to be announced in the coming weeks.

“Our legal team met with the FBI and the DOJ yesterday to begin processing background checks for incoming appointees,” Bedingfield said, adding that they need investigatory resources for expedited background checks.

Psaki touted the “incredible team” of national security experts and Biden’s experience.

“He knows his way around the situation room,” Psaki said. “We’ve had extraordinary cooperation with civil servants, employees at State, foreign service officers – and the backbones of our institutions are those employees.”

She added: “We’re hopeful that continues.”

The agency contact and Biden’s expected briefings come after GSA chief Emily Murphy, late Monday, informed Biden that her agency has formally ascertained him as the apparent winner of the 2020 presidential election and would move ahead with transition proceedings, ending a weeks-long standoff in which the Biden transition team accused the GSA of withholding critical transition resources needed for a smooth transfer of power.

Soon after, President Trump thanked Murphy for her handling of the ascertainment process, while pledging to continue his legal challenge of the election results.

“I want to thank Emily Murphy at GSA for her steadfast dedication and loyalty to our Country,” Trump wrote on Twitter. “She has been harassed, threatened, and abused – and I do not want to see this happen to her, her family, or employees of GSA. Our case STRONGLY continues, we will keep up the good fight, and I believe we will prevail!”

MEADOWS PUSHED TRUMP TO ALLOW TRANSITION TO BEGIN: SOURCES

“Nevertheless, in the best interest of our Country, I am recommending that Emily and her team do what needs to be done with regard to initial protocols, and have told my team to do the same,” Trump added.

Sources told Fox News that Murphy's letter, and the president’s follow-up tweet, were things that had been "culminating," but were pushed along after the Trump campaign's Pennsylvania lawsuit was tossed out by a judge over the weekend, and after Michigan's certification of Biden as the winner in the key battleground state on Monday afternoon.

White House chief of staff Mark Meadows was one of the driving forces behind President Trump's decision to allow the presidential transition to begin, two sources familiar with their discussions told Fox News.

Trump, Tuesday morning, though, tweeted: “Remember, the GSA has been terrific, and Emily Murphy has done a great job, but the GSA does not determine who the next President of the United States will be.”

The GSA and Murphy had faced intense bipartisan criticism in recent weeks over the decision to hold off on recognizing Biden as president-elect. The Biden transition team had threatened legal action, accusing the GSA of threatening national security and hampering preparations to combat the coronavirus pandemic by failing to provide support for the incoming administration.

Murphy said her decision was based on “recent developments involving legal challenges and certifications of election results.” Earlier Monday, Michigan voted to certify its election results and the Pennsylvania Supreme Court threw out a Trump campaign challenge that sought to invalidate thousands of absentee ballots in Allegheny County. 

Since ascertainment, the Biden transition team said the GSA “has been responsive and helpful in providing access to necessary resources,” noting that they are working on “logistical support,” such as requesting email accounts and government-issued laptops.

Inauguration Day is scheduled for Jan. 20, 2021.