The U.S. Senate has confirmed former Senator Chuck Hagel as the new Pentagon chief, after four Republicans joined Democrats to approve his nomination, BBC News reported.

The former Republican Nebraska senator was confirmed by 58-41.

Hagel will replace outgoing Defense Secretary Leon Panetta, who was confirmed by 100-0 in June 2011.

Two weeks ago, Republicans delayed a vote, questioning 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 defense secretary, after a week-long recess.

President Barack Obama's Democratic Party holds a 55-45 edge in the chamber, and Hagel ultimately only needed 51 votes to be confirmed.

Republican Senators Thad Cochran, Rand Paul, Richard Shelby and Mike Johanns voted in favor of Hagel's appointment.

After the acrimonious nomination fight, President Obama said he was pleased there had been at least some bipartisan support for Hagel.

"I am grateful to Chuck for reminding us that when it comes to our national defense, we are not Democrats or Republicans. We are Americans, and our greatest responsibility is the security of the American people," said Obama.