U.S. President Barack Obama has nominated Chuck Hagel as his next defense secretary, and presidential counterterrorism adviser John Brennan to lead the Central Intelligence Agency (CIA).
Obama announced the nominations on January 7 in Washington, D.C..
Hagel and Brennan's nominations now must face a vote of approval by the U.S. Senate, which is controlled by Obama's Democratic Party.
But Obama's nominations are seen as potentially controversial picks for his second-term national-security team.
Hagel is a Vietnam War veteran known for his criticism of Israel's threats to carry out a military strike against Iran. He has irritated some supporters of Israel by making a reference to the "Jewish lobby" in the United States.
He also has backed efforts to bring Iran to the negotiating table for future peace talks on Afghanistan.
But although Hagel is a former Republican senator, he has faced criticism from congressional Republicans, who claim he is anti-Israel and soft on Iran.
John Cornyn, the second-ranking Senate Republican, said in a statement that making Hagel the U.S. defense secretary would be "the worst possible message we could send to our friend Israel and the rest of our allies in the Middle East."
Despite the criticism, no Republican lawmakers have threatened to try to block Hagel's nomination.
Profile: Secretary Of Defense Nominee Chuck Hagel
Brennan, who spent 25 years at the CIA, played a crucial role in the planning of the 2011 raid that killed Al-Qaeda leader Osama bin Laden.
His tenure in the CIA included the job of station chief in Saudi Arabia, as well as a variety of other posts -- including deputy executive director under George W. Bush.
Obama had first considered naming Brennan as CIA director after the 2008 presidential election.
But Brennan withdrew his name from consideration for the spy agency's top post in 2008 amid questions about his connection to the heavily criticized interrogation techniques used during the Bush administration.
Profile: CIA Director Nominee John Brennan
On January 7, Obama described Hagel as "the leader our troops deserve" and an "American patriot" who enlisted in the army and volunteered to be a soldier in Vietnam.
"Chuck Hagel's leadership of our military would be historic," Obama said. "He'd be the first person of enlisted rank to serve as secretary of defense, one of the few secretaries who have been wounded in war, and the first Vietnam veteran to lead the department."
Obama described Brennan as a CIA veteran who "knows what our national security demands: intelligence that provides policymakers with the facts, strong analytic insights, and a keen understanding of a dynamic world."
Obama added that during his first term as president, "as my adviser for counterterrorism and homeland security, John developed and has overseen our comprehensive counterterrorism strategy -- a collaborative effort across the government, including intelligence, and defense, and homeland security, and law-enforcement agencies."
With reporting by AP and Reuters