Chuck Hagel, US President Barack Obama's nominee for secretary of defense, was grilled at his confirmation hearing on Thursday over controversial remarks he has made in the past.

Challenged by the Senate Armed Services Committee on his comments on Israel, Iran, nuclear weapons and defense cuts, Hagel said he was proud of his record.

"No one individual vote, quote, or statement defines me, my beliefs or my record. My overall worldview has never changed," said the former two-term Republican senator from Nebraska.