One critical piece of U.S. President Joe Biden's national security team came into place Thursday, while the White House and top lawmakers pushed for the swift confirmation of more key nominees to help take on growing international challenges.

Director of National Intelligence (DNI) Avril Haines became the first of the president's picks to take office. The first female DNI, she was sworn in early Thursday, less than 24 hours after being confirmed by the Senate by a vote of 84-10.

Shortly after her swearing-in, Haines took part in the president's daily intelligence briefing and reached out to members of the country's intelligence agencies, saying in a statement that their work "has never been more vital to our nation's security or prosperity."

Haines' quick confirmation drew praise from Republicans and Democrats, who emphasized the country has little time to spare.

FILE - Sen. Marco Rubio, R-Fla., Jan. 19, 2021.

"I am pleased my Senate colleagues joined me in swiftly confirming Director Haines," Marco Rubio, the top Republican on the Senate Intelligence Committee, said in a statement before the final tally was in. "Our adversaries will not stand by and wait for the new administration to staff critical positions."

FILE - Sen. Mark Warner, D-Va., Jan. 28, 2020.

The committee's top Democrat, Senator Mark Warner, also praised the bipartisan effort to confirm Haines, saying her role as the nation's top intelligence official is of "critical importance."

"After being deliberately undermined for four years, the intelligence community deserves a strong, Senate-confirmed leader to lead and reinvigorate it," Warner said.

There was also movement Thursday on the nomination of retired General Lloyd Austin, former commander of U.S. forces in the Middle East and South Asia (U.S. Central Command), to be Biden's secretary of defense. Austin would be the first Black secretary of defense.

Both the House and the Senate voted to grant Austin a legally required waiver to serve in the civilian post less than seven years after retiring from the military, with the Senate setting a final confirmation vote for early Friday.

FILE - Secretary of Defense nominee Lloyd Austin, a recently retired Army general, speaks during his conformation hearing before the Senate Armed Services Committee on Capitol Hill, Jan. 19, 2021.

"Even as power changes hands from one administration to the other, the work of keeping our nation safe must not be paused or be disrupted," new Senate Majority Leader Chuck Schumer told fellow lawmakers Thursday, urging them to move with haste on the nominations for the top posts at the departments of Homeland Security, State and Treasury.

"Foreign adversaries will seek to exploit this period of transition, and we cannot allow America's military, intelligence and national security policy to be disrupted by staffing delays."

The Senate is also expected to move on other key nominees, such as former Ambassador William Burns, tapped to run the Central Intelligence Agency, Washington's premiere spy agency.

Russian threats

Already, the Biden national security team is facing some key challenges, from both the coronavirus pandemic and U.S. adversaries.

The Biden administration announced Thursday that it was seeking a five-year extension of New START, one of the last remaining arms control treaties with Russia.

The treaty, which limits the U.S. and Russia to deploying no more than 1,550 strategic nuclear warheads and puts limits on the missile delivery systems, is set to expire in February.

White House press secretary Jen Psaki also confirmed Thursday that Biden was asking the intelligence community for assessments on suspect Russian actions, including the SolarWinds cyberhack, interference in November's presidential election, the use of chemical weapons against opposition leader Alexei Navalny and alleged bounties on U.S. soldiers in Afghanistan.

Haines, a former deputy director of the Central Intelligence Agency and a former White House aide, told lawmakers during her confirmation hearing Tuesday that Russia's use of influence operations, in particular, was a concern.

"I've certainly seen Russia's use of active measures in a variety of campaigns to exacerbate the divisions in this country and to promote extremism, in a sense," Haines said.

In his confirmation hearing Tuesday, Austin also warned about the Kremlin, saying that although Russia is a power "in decline," it can still do "a great deal of damage" in cyberspace.

Looking inward

Both Haines and Austin also told lawmakers that much of their focus would be inward as they seek to help restore trust and confidence in the intelligence community and the military.

"To be effective, the DNI must never shy away from speaking truth to power. Ever. Especially when doing so may be inconvenient or difficult," Haines said.

For his part, Austin said he would make it a priority to stamp out extremism and illegal behavior within the military.

"The job of the Department of Defense is to keep America safe from our enemies, but we can't do that if some of those enemies lie with our own ranks," he said.

"This [extremism] has no place in the military of the United States of America," Austin added, describing it as part of a broader battle.

"I will fight hard to stamp out sexual assault, and to rid our ranks of racists and extremists, and to create a climate where everyone fit and willing has the opportunity to serve," he said.

VOA's Katherine Gypson contributed to this report.