WASHINGTON (Reuters) - The U.S. special forces team that hunted down Osama bin Laden was under orders to kill the al Qaeda mastermind, not capture him, a U.S. national security official told Reuters.

"This was a kill operation," the official said, making clear there was no desire to try to capture bin Laden alive in Pakistan. (Reporting by Mark Hosenball, writing by Matt Spetalnick)