Hagel: US 'can't dictate to the world'

“We can't dictate to the world, but we must engage in the world. We must lead with our allies,” Hagel said in his first speech as secretary. “Allies are, as everyone in this room knows, particularly important. No nation — as great as America is — can do any of this alone.”

Hagel was sworn in as Defense secretary Wednesday morning, less than 24 hours after he was confirmed by the Senate.

The Pentagon's Director of Administration and Management Michael Rhodes administered the oath for Hagel in a private ceremony.

Hagel, the first Vietnam veteran to run the Pentagon, also acknowledged in his remarks the budget issues and other challenges that lie ahead in his tenure.

Read more on The Hill's DEFCON blog.