WASHINGTON (AP) — The secretary of the Navy is ordering a pair of security reviews -- focusing on how well the Navy protects its bases, and how accurately it screens its workers.

And President Barack Obama is ordering a review of security standards for contractors and employees across federal agencies.

The reviews follow Monday's shooting rampage at the Washington Navy Yard by a gunman who killed 12 people before dying in an exchange of fire with police.

Officials say Aaron Alexis had been hearing voices and had been undergoing treatment for mental problems including paranoia in recent weeks, but he still kept his security clearance.

Meanwhile, the FBI says Navy Yard gunman Aaron Alexis had a shotgun when he entered a building and got a handgun inside after he started firing.

Valerie Parlave, head of the FBI's field office in Washington, said Tuesday they don't have any information that he had an AR-15 assault rifle in his possession.

There has been conflicting information about the weapons Alexis used. Previously, a law enforcement official told The Associated Press the gunman had two handguns he took from officers.

Parlave says Alexis arrived in the Washington area late last month and had been staying at local hotels in the days leading up to the shooting rampage.

D.C. Police Chief Cathy Lanier says officers with AR-15s arrived at the building within seven minutes of the call.