* White House announcements expected later on Monday
* Republican Chuck Hagel Obama's defense secretary pick
* Obama to tap counterterrorism adviser John Brennan for CIA
* Move fills out key team for Obama
WASHINGTON, Jan 7 (Reuters) - President Barack Obama on Monday will announce the nominations of Republican Chuck Hagel as his next defense secretary and White House counterterrorism adviser John Brennan as the new CIA director, a senior administration official said.
The choice of Hagel, a maverick former Republican senator and decorated Vietnam veteran, had been widely tipped to replace Leon Panetta at the Pentagon. The move will likely set up a tough Senate confirmation battle against critics who have attacked his record on Israel and Iran.
Brennan, who formerly served at the CIA, will succeed retired general David Petraeus, who resigned amid a scandal over an extramarital affair with his biographer.
The addition of Hagel and Brennan, along with Senator John Kerry as nominee for secretary of state, would fill out the team Obama will rely upon as he faces daunting challenges of winding down the war in Afghanistan, dealing with the Iranian nuclear standoff and curbing Pentagon spending.
The announcements are expected to come later on Monday.
Hagel, a Vietnam veteran and former Nebraska senator who left the Senate in 2008, faces tough criticism from many Republicans over actions they see as opposing Israel's interests, including votes against U.S. sanctions on Iran and remarks about what he called a "Jewish lobby" in Washington. Hagel has also been critical of the size of the U.S. military.
But the White House appears confident it can get overcome the criticism to win confirmation of Hagel in the Democratic-led Senate.
Retired Army General Stanley McChrystal, speaking on NBC's "Today" program, said Hagel's statements should not disqualify him.
"If President Obama trusts him, I think Senator Hagel has the experience. He's certainly got the qualities as a person," said McChrystal, the former top U.S. commander in Afghanistan who resigned in 2010. "I think that level of trust and relationship between those people and with other members of the cabinet are the most important thing."
Brennan has served as Obama's chief counterterrorism adviser since 2008.
"John Brennan's career of service and extraordinary record has prepared him to be an outstanding director of the CIA. ... Brennan has the full trust and confidence of the president," the senior admin official
"For four years, he has seen the president every day, and been by his side for some of his toughest decisions - including the decision to launch the bin Laden raid," the official added.