President Obama urged a divided Senate Monday to quickly confirm twonew members of his national security team, though Republicans might notcooperate when it comes to Defense Secretary nominee Chuck Hagel.

"ChuckHagel is the leader our troops deserve," Obama said in an East Roomceremony, praising him for his service in Vietnam, his business career,and his two terms as senator -- a Republican senator -- from Nebraska.

CurrentSenate Republicans, however, have questioned their former colleague'scommitment to Israel's security and his attitude towards Iran and itsnuclear program.

Obama also announced the nomination of White House counter-terrorism adviser John Brennan to be the new director of the CIA.

Notingthat "the work of protecting our nation is never done," Obama said hissecond term security team faces challenges that range from wrapping upthe war in Afghanistan to cyber security.

In pointedly urging theSenate for quick confirmations, Obama said: "When it comes to nationalsecurity, we don't like to leave a lot of gaps."

Hagel is slatedreplace retiring Pentagon chief Leon Panetta, who also led the CIAearlier in Obama's term. Brennan, meanwhile, would replace DavidPetraeus, who resigned from the CIA in November after admitting anextramarital affair.

Hagel did not address the Republicancriticism during brief remarks at the White House, telling Obama hewould always provide "honest and informed" counsel as defense secretary.

SomeSenate Republicans said that, during his political career, Hagel hasbeen too critical of Israel and too soft on Iran and its nuclearambitions. Sen. John Cornyn, R-Tex., said, "the worst possible messagewe could send to our friend Israel and the rest of our allies in theMiddle East is Chuck Hagel."

Obama and other Democrats praisedHagel's record, including two Purple Hearts for service in Vietnam and asuccessful business career before his 1996 Senate election.

"ChuckHagel's candor, judgment, and expertise will serve him well as our nextsecretary of defense," said Sen. Jack Reed, D-Ill., a member of theSenate Armed Services Committee that will hold confirmation hearings.

Asfor Brennan, Obama praised his adviser's "keen understanding of adynamic world," and noted that he created the National Counter-terrorismCenter. He also praised Brennan's work ethic, saying "I'm not sure he'sslept in four years."

Obama considered him for the CIA after the2008 election. Brennan withdrew after critics noted that he worked forthe CIA at a time that it used enhanced interrogation techniques againstterrorist suspects; Brennan said he opposed those techniques, includingwater boarding.

As a top adviser to Obama, Brennan has also beeninvolved in the administration's increased used of unmanned drones forsurveillance and for attacks on suspected terrorists.

ThankingObama for his nomination, Brennan said he would push to get the CIA "thetools it needs to keep our nation safe." He also pledged to bebipartisan, saying he was neither a Republican nor a Democrat.

Brennan's CIA nomination is not without its critics.

LauraW. Murphy, director of the Washington Legislative Office for theAmerican Civil Liberties Union, said: "The Senate should not moveforward with his nomination until all senators can assess the role ofthe CIA -- and any role by Brennan himself -- in torture, abuse, secretprisons, and extraordinary rendition during his past tenure at the CIA."

TheHagel and Brennan nominations are Obama'a latest moves as he re-toolshis administration ahead of a second term that starts Jan. 20.

Late last month, Obama nominated Sen. John Kerry, D-Mass., to be Secretary of State.

Thepresident is also looking to replace Treasury Secretary TimothyGeithner and Environmental Protection Agency administration LisaJackson, both of whom are planning to leave this month.

The Hagel nomination, for now at least, is drawing more attention, particularly from supporters of Israel.

AbrahamH. Foxman, national director the Anti-Defamation League, said herespects "the president's prerogative" to nominate who he wants, but hehopes the confirmation hearings will give Hagel a chance to "addressconcerns about his positions."

Said Foxman: "I particularly hopeSenator Hagel will clarify and explain his comments about the "JewishLobby" that were hurtful to many in the Jewish Community."

JeremyBen-Ami, president of an organization called J Street, said Hagelunderstands "the appropriate uses and limitations" of U.S. power, andbeen a staunch supporter of Israel's security.

Praising Obama forfollowing through on the nomination in face of Republican criticism,Ben-Ami said "this sets an important precedent. Hopefully, qualifiedcandidates will no longer be prevented from serving the nation by 'SwiftBoat'-style attacks that distort their records and caricature theirbeliefs."