Chuck Hagel sworn in as US defence secretary
Chuck Hagel has been sworn in as the new US defence secretary, a day after the Senate approved his appointment following a bruising nomination battle.
The former Republican Nebraska senator will speak at the Pentagon later in his first public remarks as Pentagon chief.
Mr Hagel was confirmed by a 58-41 vote after Republicans stalled his nomination, questioning his past positions on Israel and Iran.
He replaces Leon Panetta, who was confirmed by 100-0 in June 2011.
"I am honoured that President Obama and the Senate have entrusted me to serve our nation once again," Mr Hagel said in a statement.
Two weeks ago, Republicans delayed a vote, questioning Mr Hagel's past positions on Israel and Iran, and his qualifications for the post.
But they dropped the filibuster stalling tactic, the first time it has ever been used to delay confirmation of a defence secretary, after a week-long recess.
North Korea allegation
President Barack Obama's Democratic Party holds a 55-45 edge in the chamber, and Mr Hagel ultimately only needed 51 votes to be confirmed.
Republican Senators Thad Cochran, Rand Paul, Richard Shelby and Mike Johanns voted in favour of Mr Hagel's appointment.
President Obama said he was pleased there had been at least some bipartisan support for Mr Hagel.
"I am grateful to Chuck for reminding us that when it comes to our national defence, we are not Democrats or Republicans. We are Americans, and our greatest responsibility is the security of the American people," said Mr Obama.
Earlier on Tuesday, Mr Hagel, a decorated Vietnam veteran, passed a crucial procedural vote that needed the support of 60 senators.
Among the sticking points in Mr Hagel's nomination process was a remark he made in a 2008 book that the "Jewish lobby" intimidated decision-makers on Capitol Hill.
Republican senators also said they feared the 66-year-old Mr Hagel would be too lax on Iran.
During his time as a senator, Mr Hagel angered Republican party leaders when he pilloried former President George W Bush's handling of the Iraq war.
Ted Cruz, an outspoken conservative first-term senator from Texas, recently suggested without evidence that Mr Hagel had accepted payments from North Korea.
During his confirmation hearing in January, Mr Hagel sought to reassure the Senate armed services committee that he was "fully committed" to preventing Iran from obtaining a nuclear weapon.
He also apologised for the "Jewish lobby" comment, saying he could not be defined by any single quote.
Mr Hagel's Democratic Party supporters produced other remarks and evidence they said showed he would stick to existing US policy on Israel and Iran.
The White House had warned of great risks in leaving the Pentagon without a leader at a time of budget challenges and while the US has troops in Afghanistan.
Senate Democrats blasted their colleagues for the blocking tactics, but some Republicans protested that they needed more time to weigh the nomination.
Others, including several senior Republicans on the armed services committee, said outright that they would not back Mr Hagel.