State Dept. condemns arrests, repression in Russia

International superstar Lady Gaga sang the National Anthem into a gold microphone on the West Front steps of the Capitol for the inaugural ceremonies -- to cheers and applause from the limited audience.

Gaga wore a long sleeve black dress with a pouffy red skirt and golden dove broach with an olive branch across her heart..

Captain Andrea Hall, the first African American female firefighter to become captain of the Fire Rescue Department in South Fulton, Georgia, read the pledge of allegiance.

Sen. Amy Klobuchar, D-Minn., one of the chairs on the Joint Congressional Committee on Inaugural Ceremonies, kicked off the inauguration by acknowledging the attack on the Capitol two weeks ago.

"Two weeks ago when an angry violent mob staged an insurrection and desecrated this temple of our democracy, it awakened us to our responsibilities as Americans," Klobuchar began. "This is the day when our democracy picks itself up, brushes off the dust, and does what America always does: goes forward as a nation, under God, indivisible, with liberty and justice for all."

She also acknowledged the historic nature of Vice President-elect Kamala Harris' ascension to office as the first woman, first Black woman and first South Asian American to be sworn in as vice president.

"When she takes the oath of office, little girls and boys across the world will know that anything and everything is possible," Klobuchar said. "And in the end, that is America, our democracy, a country of so much good, and today, on these Capitol steps and before this glorious field of flags, we rededicate ourselves to its cause."

Guests at Wednesday's inauguration are all wearing masks, a sign of the COVID-19 pandemic which has officially killed more than 400,000 Americans. 

And following the deadly insurrection at the Capitol on Jan. 6, several members of Congress are wearing body armor, ABC News Senior White House Correspondent Mary Bruce reported. 

ABC reporter Benjamin Siegel saw some Democrats greeting each other by tapping each other on the chest, a “sort of a subtle acknowledgement that they are prepared,” Bruce said.

-ABC News’ Molly Nagle, Benjamin Siegel and Mary Bruce

Supreme Court Chief Justice John Roberts and Justice Sonia Sotomayor are administering the oaths of office at the presidential inaugural ceremonies on Capitol Hill.

The vice president-elect -- making history as the first woman, first Black woman and first South Asian American vice president -- will be sworn in by Sotomayor, the first Latina Supreme Court Justice.

All three Trump appointees to the high court -- Justices Brett Kavanaugh, Neil Gorsuch and Amy Coney Barrett are also in attendance with Barrett appearing in public in her black judicial robe for the first time.

The court says Stephen Breyer, Samuel Alito and Clarence Thomas opted not to attend because of public health risks from the coronavirus pandemic. 

It's the first time since 2001 that the entire court is not in attendance at an inauguration.

-ABC News' Devin Dwyer