WASHINGTON, Sept. 17 (Xinhua) -- U.S. President Barack Obama has ordered a review of standards for contractors and employees in federal government in the wake of the Navy Yard shooting in Washington, D.C., the White House said Tuesday.

White House Spokesman Jay Carney made the announcement during his regular press briefing, saying the review is to be conducted by the Office of Management and Budget (OMB).

"At the president's direction, OMB is examining standards for contractors and employees across federal agencies," said Carney said Tuesday. "This is a matter that the president believes and has believed merits review."

The OMB review will examine the "oversight, nature and implementation of security and suitability standards for federal employees and contractors." It is in addition to an ongoing review of intelligence community contractors Obama ordered after former U. S. National Security Agency contractor Edward Snowden began leaking a trove of classified documents regarding U.S. government' s secret surveillance programs on its own citizens and on other countries.

The White House announced the review as questions grew as to how Aaron Alexis, a former Navy reservist with a checkered history and mental problems, was able to get a security clearance to enter the military installation.

Alexis was accused of fatally shooting 12 people before he was gunned down by police in Monday's carnage.