Trump-Biden transition updates: Trump continues to tout he won election at Ga. rally

Moments before Trump left the White House to head to Georgia for a campaign rally for Senate Republicans, the president, in a tweet, called on Gov. Brian Kemp to “immediately ask for a Special Session of the Legislature” in his continued efforts to overturn the election.

He continued to blast local leaders, claiming that the governor's “people are refusing to do what you ask,” adding “What are they hiding.”

"But you never got the signature verification! Your people are refusing to do what you ask. What are they hiding? At least immediately ask for a Special Session of the Legislature. That you can easily, and immediately, do," the president tweeted, referring to a previous tweet from Kemp saying he had asked for a signature audit.

Kemp announced earlier Saturday that would not be attending Trump’s rally in support of GOP Sens. Kelly Loeffler and David Perdue, whose runoff elections occur in January.

The Georgia governor's communications director confirmed to ABC News that the president called Kemp Saturday morning.

-ABC News' Elizabeth Thomas

Georgia Gov. Brian Kemp responded Saturday to a tweet from Trump earlier in the day saying he will "easily & quickly win Georgia" if Kemp and the secretary of state "permit a simple signature verification."

"As I told the President this morning, I’ve publicly called for a signature audit three times (11/20, 11/24, 12/3) to restore confidence in our election process and to ensure that only legal votes are counted in Georgia," Kemp tweeted, just hours ahead of Trump's rally in the Peach State.

Trump has used his bully pulpit to slam Kemp, a longtime Trump supporter, as he has refused to echo the president’s baseless allegations of fraud in Georgia.

The president has tweeted that Kemp was "hapless" and should "overrule his obstinate secretary of state," Brad Raffensperger -- also a Republican backer of Trump -- after the latter refused to intervene to help Trump.

"The governor's done nothing," Trump said during a Fox News interview. "He's done absolutely nothing. I'm ashamed that I endorsed him."

The Twitter exchange comes as Trump is set to speak at a rally for Republican Senate candidates in the state -- races that will determine the balance of the Senate.

On Friday, Kemp was expected to meet Vice President Mike Pence, also in the state for a rally, on the tarmac upon his arrival in Savannah, but he could not due to a family emergency.

Kemp is not attending Trump’s rally Saturday, according to his Communications Director Cody Hall.

-ABC News' Elizabeth Thomas, Jordyn Phelps, Ben Gittleson, Olivia Rubin, Will Steakin, Quinn Scanlan, Rachel Scott and Matthew Mosk

White House coronavirus response coordinator Deborah Birx said on Friday that her role in the Biden administration remains unclear.

“I don’t know what my role will be come Jan. 20,” Birx told Rhode Island station WPRI.

Earlier this week, Biden's team had made contact with both Birx and National Institute of Allergy and Infectious Diseases Director Dr. Anthony Fauci, holding separate meetings with the two White House coronavirus task force officials.

"I was privileged to brief them on Monday," Birx said in a separate interview Friday with ABC Des Moines affiliate WOI. "I will tell you they had very good questions, very well informed questions and as a civil servant, I always stand ready to serve any administration."

ABC News reported in November that Birx expressed a desire to continue serving in a Biden administration, according to colleagues.

However, Birx has found herself in an increasingly complicated position as she combats the virus while serving a president who has ignored science and downplayed the pandemic.

Her rosy presentations from the White House podium and presence alongside Trump at news conferences this spring -- as well as her attempt to explain away Trump's suggestion in April that Americans could inject disinfectant to treat the virus -- have hurt her credibility and led to charges she has enabled the president.

-ABC News' Ahmad Hemingway and Ben Gittleson

As President Donald Trump and his allies continue their legal barrage in an effort to overturn the presidential election despite a succession of adverse rulings, some state and local election officials are starting to cry foul.

In Michigan Thursday, Republican lawyers were back in court seeking an audit of election results in the heavily-Democratic county that is home to Detroit -- even after the state's Supreme Court had already rejected an earlier request from the same group to halt certification. An exasperated lawyer for the city pleaded with the judge to do something.

"They are trying to use this court in a very, very improper way," said Detroit city attorney David Fink. "We ask this court not just to deny the relief that is requested but to grant significant sanctions, because this has to stop."

The attorney for the Trump poll observers shot back: "I didn't realize I was such a threat to our republic by simply asking that this court to enforce our constitutional right."

The Michigan case is not isolated, and opponents say they are starting to see the relentless effort as abusive. In just the past week, at least five new cases were filed on the president's behalf. Between the Trump campaign and the president's allies, there have now been at least 46 lawsuits filed challenging the 2020 presidential contest -- many employing the same recycled fraud claims and witness affidavits.

And if more cases land on court dockets with glaring errors or what judges have described as anemic evidence, legal experts told ABC News that even some slow-to-boil judges may see no choice but to impose sanctions.

"You could see a court saying, 'Enough is enough,'" said Daniel I. Weiner, deputy director of the Brennan Center for Justice's Election Reform Program at New York University.

-ABC News' Olivia Rubin, Matthew Mosk, Luke Barr, Ali Dukakis