Just 16 days before he's set to leave office, President Donald Trump will headline a rally for Sens. Kelly Loeffler and David Perdue in Dalton, Georgia.

The rally comes on Jan. 4, the night before the two sitting senators face separate Democratic opponents -- Rev. Raphael Warnock and Jon Ossoff, respectively -- in two runoffs that could determine control of the Senate. The makeup of the Senate is currently projected to be 50 Republicans and 48 Democrats and left-leaning independents. If Warnock and Ossoff win, pushing the balance to 50-50, the Democrats would control both the House and Senate, due to Kamala Harris casting the deciding vote in the upper chamber.

Dalton is in Georgia's 14th Congressional District, which makes up the northwest corner of the state and is perhaps the state's most conservative district. Its congresswoman-elect, Marjorie Taylor Greene, has supported QAnon conspiracies in the past and has fully embraced, defended and perpetuated Trump's false narrative about the election.

The 14th Congressional District is also doing the worst of the 14 districts in terms of turnout for the runoff, according to Georgia Votes, which is analyzing the secretary of state's data.

Trump made his one and only appearance in Georgia during the runoff campaign on Dec. 5, when he spent nearly two hours ticking off baseless conspiracies about the presidential election and went on a tangent about how he didn't want to come to appear at the rally.

-ABC News' Quinn Scanlan

Continuing Biden and Vice President-elect Kamala Harris' focus on the worsening coronavirus pandemic Tuesday, the transition team announced nine additional members of the White House COVID-19 response team.

The new members will help focus on the "three crucial aspects of the COVID-19 response strategy: supply chain management, vaccinations, and testing," the transition team said.

"To recover from this pandemic, we must take aggressive action to manufacture, distribute, and administer vaccines, testing, and personal protective equipment in an equitable way. These individuals are deeply qualified and will restore public trust in the pandemic response by leading with facts, science, and integrity,” Biden said in a statement announcing the new members.

-ABC News' Beatrice Peterson

Following a meeting with his COVID-19 task force, Biden delivered remarks on the state of the worsening coronavirus pandemic and slammed the Trump administration for falling behind its goal in distributing vaccines to Americans.

"As I long feared and warned, the effort to distribute and administer the vaccine is not progressing as it should," Biden said. "If it continues to move as it is now, it's going to take years, not months, to vaccinate the American people."

The president-elected noted how officials working on "Operation Warp Speed," the federal government's vaccine program, had predicted this month 20 million vaccinations by the end of the year, but with just a few days left in 2020, the Centers for Disease Control has recorded about 2.1 million Americans as having received a dose.

"This will take more time than anyone would like and more time than the promises from the Trump administration have suggested. This is going to be the greatest operational challenge we've ever faced as a nation," Biden said. "And we're going to get it done."

Biden repeated his intention to invoke the Defense Production Act to compel companies in the private sector to accelerate the production of materials needed for vaccines and testing, as well as protective gear. He also announced that his administration will launch a public education campaign to promote vaccine acceptance and equity.

"We're also going to make sure vaccines are distributed equitably, so every person who wants a vaccine can get it no matter the color of their skin or where they live. We're going to ensure vaccinations are free of charge," he said.

Biden, overall, painted a bleak picture of soaring infections and deaths in the coming weeks, acknowledging the "grim milestone" of the U.S. crossing 330,000 deaths and saying the county may not see improvement until March. He implored Americans to wear a mask and social distance in the meantime -- and called on Trump to set an example.

"It would make a huge difference for President Trump to say 'wear masks.' I hope the President will clearly and unambiguously urge all Americans to take the vaccine once it's available," he said.

After golfing in West Palm Beach, Trump lashed out at Republicans on Twitter Tuesday in response to Senate Majority Leader Mitch McConnell blocking two efforts to pass $2,000 relief checks with a unanimous vote, saying those in his party have a “death wish” for opposing the House-passed measure.

“Unless Republicans have a death wish, and it is also the right thing to do, they must approve the $2000 payments ASAP. $600 IS NOT ENOUGH! Also, get rid of Section 230 - Don’t let Big Tech steal our Country, and don’t let the Democrats steal the Presidential Election. Get tough!” Trump said on Twitter.

It’s unclear at this point how McConnell plans to proceed, but if he does intend to tie those three issues together into one bill, as he suggested he might on the Senate floor earlier Tuesday citing the president's demands, it’s unlikely to pass.

-ABC News' Elizabeth Thomas and Mariam Khan

Following a briefing with his COVID-19 advisory team on Tuesday, Biden is expected to continue his criticism of the Trump administration in afternoon remarks on the coronavirus pandemic from Wilmington, Delaware, and home in on what his team has characterized as the lagging pace of vaccine distribution.

According to a transition official, Biden will provide an update on the current state of the pandemic and give a dire prediction that, tragically, infection and death rates will rise in the coming weeks. Biden is also expected to address the current administration falling short on its pace for vaccinations, the official said, as well as his plan to get 100 million vaccinations in 100 days.

Biden on Monday slammed the Trump administration for, he said, leaving security agencies "hollowed out" and for creating "roadblocks" for his transition team seeking access to key national security information -- a comment that acting Defense Secretary Christopher Miller has pushed back on, saying the Biden team has already been given more interviews and documents than they initially requested.

Vice President-elect Kamala Harris and her husband, Doug Emhoff, on Tuesday morning are slated to receive their first doses of the COVID-19 vaccine in Washington, D.C., where Harris may also comment on the incoming administration's vaccine distribution plans.

Trump, meanwhile, continued to contest the election on Twitter Tuesday morning -- with three weeks until Biden's inauguration -- criticizing Republican leadership as "pathetic," saying they "only want the path of least resistance" and "only know how to lose." He also attacked Republican lawmakers over their handling of the defensing funding bill as the Senate is expected to override Trump's presidential veto for the first time in his presidency by the end of the week.

After Trump changed course on Sunday and signed the coronavirus relief and government funding bill to avert a shutdown -- though not in time to prevent unemployment benefits to millions of Americans from lapsing -- the House of Representatives on Monday approved Trump's call to increase the coronavirus relief payments from $600 to $2,000.

But its fate in the Senate is uncertain. Senate Majority Leader McConnell has declined to reveal how he will proceed or even whether he’ll bring the proposal up for a vote. Democrats are seizing the opportunity to force Republicans into a difficult position -- either backing or defying Trump.

-ABC News' Molly Nagle and Ben Gittleson