Despite Joe Biden's transition being stalled, the president-elect is moving forward with selecting his cabinet.

According to sources familiar with the decision, Biden is expected to name Antony Blinken, a longtime foreign policy aide with decades of experience in Washington, as his nominee for secretary of state. The announcement could come as soon as Tuesday.

Blinken has been one of Biden's closest advisers for decades, from Biden's time on the Senate Foreign Relations Committee to the Obama White House and the 2020 presidential campaign.

A former deputy secretary of state under President Obama, Blinken began his career in the Clinton State Department and later moved to the White House and National Security Council under President Clinton.

A spokesman for Biden's transition declined to comment.

-ABC News' Martha Raddatz, Katherine Faulders, John Santucci, Molly Nagle and Benjamin Siegel

The Trump campaign released a statement Sunday night distancing itself from attorney Sidney Powell, saying she's not a member of the "Trump Legal Team," despite President Trump previously announcing that she was.
 

"Sidney Powell is practicing law on her own. She is not a member of the Trump Legal Team. She is also not a lawyer for the President in his personal capacity," Trump campaign attorneys Rudy Giuliani and Jenna Ellis said in a statement.

The statement comes after Powell advanced a series of unproven election claims in an interview on Newsmax and at a recent press conference on behalf of the campaign, portions of which were retweeted by the official GOP Twitter account.
 

The president last week announced Powell as a member of his legal team along with Giuliani, Ellis, and attorneys Joseph diGenova and Victoria Toensing.

U.S. Senator Lisa Murkowski (R-Alaska) released a statement today urging President Trump to respect the outcome of the 2020 election.

"President Trump has had the opportunity to litigate his claims, and the courts have thus far found them without merit," her statement said in part. "A pressure campaign on state legislators to influence the electoral outcome is not only unprecedented but inconsistent with our democratic process. It is time to begin the full and formal transition process."

Murkowski has previously acknowledged Joe Biden as the president-elect.

Republican Sens. David Perdue and Kelly Loeffler said Sunday that they back the president's calls for a recount involving absentee signature matching in Georgia. 

"Anything less than that will not be a full and transparent recount," Perdue said in a campaign press release. "Georgians deserve full transparency and uniformity in the counting process."

Loeffler, in a statement a short time later said, "I fully support President Trump’s request for a recount in Georgia. We must match and verify absentee ballot signatures to their corresponding voter registration signatures, investigate all voting irregularities, and count only the votes that were legally cast.”

Signature matching will not take place during the recount, according to Gabriel Sterling, the statewide voting system implementation manager in Secretary of State Brad Raffensperger's office. He said it's "not part of this process because it's not contemplated in the law" and that they've received no evidence that signature matching was not done properly in accordance with state law. 

Sterling also said that parties were allowed to designate observers to watch the absentee signature matching process take place, but neither party did this except for just one instance in one county.

Georgia certified its election results on Friday. 

Perdue and Loeffler are facing Democrats Jon Ossoff and the Rev. Raphael Warnock in Georgia runoff elections for the U.S. Senate. 

-ABC News' Quinn Scanlan

While Biden forges ahead and continues to build out his White House team, he remains hindered by the lack of a formal concession from Trump.

The Trump administration is still not recognizing Biden as the president-elect, and Biden warned Monday "more people may die" without a the process of a formal transition as the country battles the coronavirus pandemic on top of ongoing national security concerns. 

 
Taking matters into his own hands, Biden and Vice President-elect Kamala Harris will receive a briefing on national security from security and defense advisers in Wilmington, Delaware, on Tuesday, as they stress their work must begin now and not on Jan. 20. 

 
The briefing comes as Trump makes [geo-political moves not typical of a lame-duck commander-in-chief. Two officials confirmed to ABC News on Monday that orders were expected by the end of this week to reduce troop levels in Afghanistan to 2,500 and in Iraq to 2,500 by mid-January.

 
Notably, Biden has said Harris is still getting briefings based on her role on the Senate Intelligence Committee, but it’s unclear how much she can pass on to Biden.

Pressing forward, Biden is also expected to name a number of senior White House staff as soon as this week, a group that will likely include Rep. Cedric Richmond, D-La., a key surrogate and his campaign's first national co-chair. Biden's campaign manager Jen O'Malley Dillon is expected to join the administration as deputy chief of staff, sources confirmed to ABC News.

 
While Trump has no public events on his schedule for Tuesday, Vice President Mike Pence will lead a coronavirus task force meeting at the White House as the administration faces criticism on Trump’s apparent lack of interest in managing the virus. Trump hasn’t attended a task force meeting for months.

It all comes as state certification deadlines approach for the 2020 election, and the Trump campaign, working against those deadlines, also fights against the results which voted him out of office.