Republican Sen. Lisa Murkowski of Alaska said in a statement Thursday she believes that the House responded to Trump's actions "appropriately" by impeaching him but does not say how she will vote.

"On the day of the riots, President Trump’s words incited violence, which led to the injury and deaths of Americans – including a Capitol Police officer – the desecration of the Capitol, and briefly interfered with the government’s ability to ensure a peaceful transfer of power. Such unlawful actions cannot go without consequence and the House has responded swiftly, and I believe, appropriately, with impeachment," she said in a statement.

Murkowski said she intends to hear arguments in the Senate before deciding whether she will vote to convict.

"I will follow the oath I made when sworn as a U.S. Senator. I will listen carefully and consider the arguments of both sides, and will then announce how I will vote," Murkowski said.

It's also unclear how Republican Majority Leader Mitch McConnell will vote in the Senate trial, telling Republican colleagues in a memo Wednesday he hasn't "made a final decision" on whether to vote to convict Trump.

-ABC News' Allison Pecorin

Five key Senate panels have now confirmed that they will hold confirmation hearings for Biden's top national security officials before Inauguration Day -- although it remains unlikely most of his picks will be confirmed by day one.

Avril Haines will have her hearing Friday to be Director of National Intelligence, while four others will have theirs on Tuesday -- Tony Blinken for secretary of state, Janet Yellen for Treasury secretary, Lloyd Austin for Defense secretary, and Alejandro Mayorkas for Homeland Security secretary.

The Senate Foreign Relations Committee hasn't scheduled a hearing yet for Linda Thomas-Greenfield, Biden's pick for U.N. ambassador and a member of his Cabinet, despite her being announced in November. Bill Burns, Biden's pick to be CIA director, also doesn't have a hearing scheduled yet, but Biden only announced his intention to nominate Burns Monday.

It's unclear how long after a confirmation hearing any of these Cabinet picks can be confirmed, especially with an impeachment trial -- but they'll require a committee vote and then a full Senate vote. It's likely most won't be confirmed and in position on Inauguration Day.

Biden's team has escalated pressure this week to confirm his national security Cabinet as soon as possible.

In contrast, on Trump's Inauguration Day, the Senate confirmed both John Kelly as Department of Homeland Security secretary and Jim Mattis as Department of Defense secretary, and 11 more Trump nominees already had their confirmation hearings. President Barack Obama had seven Cabinet chiefs confirmed on Inauguration Day, while six more had confirmation hearings by then and his Defense Secretary Bob Gates stayed on from the Bush administration, according to the U.S. Senate website.

-ABC News' Conor Finnegan and Molly Nagle

The White House press office has issued a statement from the president touting his military accomplishments as his time as commander-in-chief is set to expire in six days.

"United States military troops in Afghanistan are at a 19-year low. Likewise, Iraq and Syria are also at the lowest point in many years. I will always be committed to stopping the endless wars. It has been a great honor to rebuild our military and support our brave men and women in uniform. $2.5 trillion invested, including in beautiful new equipment—all made in the U.S.A.," the statement read.

-ABC News' Ben Gittleson

Incoming first lady Jill Biden on Thursday announced the re-launch of "Joining Forces," which originated in 2011 during the Obama administration and was a "a nationwide initiative calling all Americans to rally around service members, veterans, and their families and support them through wellness, education, and employment opportunities," that also had the involvement of then-first lady Michelle Obama.

"We'll continue to listen and work with you, making sure that your experiences and expertise are the north star of this effort. And that starts today. That's the promise that I made to you on the campaign trail. That we would relaunch Joining Forces and get to work on day one," Biden said during a virtual event announcing the initiative's relaunch.

The announcement comes after Biden pledged several times on the campaign trail that she would focus her work as first lady on the priorities that defined her work when her husband was vice president for eight years, including her advocacy for military families.

During Biden's remarks she talked about her excitement to work again on Joining Forces while noting her ties to the military through the deployment of her son Beau and her father who was in the Navy during World War II.

"I'm grateful and excited, and most of all, ready to get to work with all of you. And as many of you may know, or maybe you don't, but my father was a Navy signalman in World War II," Biden said. "And my son Beau served for a year in Iraq as a member of the Delaware National Guard. Now, toward the end of the campaign, I had the chance to go back to Hammonton, New Jersey, where I was born, to see the memorial that bears my father's name in our hometown Park."

The future first lady noted that Rory Brosius, a close adviser to the Biden's and is a military spouse, will be joining the White House as a special assistant to the president and executive director of Joining Forces, adding, "No one is more passionate about this work than Rory."

-ABC News' Beatrice Peterson and John Verhovek

House Democrats have opened an investigation into what law enforcement and the intelligence community knew about threats to the Capitol ahead of the Jan. 6 siege.

The investigation from the House Intelligence, Oversight, Homeland Security and Judiciary committees will also examine whether anyone with security clearances -- current or former National Security, Defense, Justice or Homeland Security officials -- participated in the riot.

The investigation will also examine the federal law enforcement response in the aftermath of the attack.

"The Committees will conduct robust oversight to understand what warning signs may have been missed, determine whether there were systemic failures, and consider how to best address countering domestic violent extremism, including remedying any gaps in legislation or policy," committee members wrote in a letter to the FBI, DHS and Office of the Director of National Intelligence.

"This still-emerging story is one of astounding bravery by some U.S. Capitol Police and other officers; of staggering treachery by violent criminals; and of apparent and high-level failures -- in particular, with respect to intelligence and security preparedness," the letter later stated.

Democrats plan to request documents and briefings from administration officials as part of the investigation -- just one of several looking into the Capitol attack.

-ABC News' Benjamin Siegel