At the Pentagon, Hagel said that while "we don't live in a risk-free society," employees deserve a safe and secure work environment.
And, he said, "obviously, something went wrong" on Monday.
He said he has ordered the Pentagon to review the physical security and access procedures at all U.S. defense facilities worldwide as well as a study of the programs used for granting and renewing the security clearances for the military, civilian employees and contractors.
And he also has asked an independent panel to undertake the same reviews, vowing that, "where there are gaps, we will close them."
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