Amos Patton, National Guardsman, allegedly shot two of his superiors at Tenn. armory

(CBS/AP) MEMPHIS - A National Guardsman was being held Friday and awaiting charges in the shooting of two of his superiors at an armory north of Memphis.

CBS affiliate WREG reports that sergeant first class Amos Patton had been disciplined before he opened fire with a handgun Thursday at the armory in Millington, Tennessee, according to a law enforcement official who had been briefed on the case. The official was not authorized to discuss the investigation publicly and spoke on condition of anonymity.

The armory, which houses a recruitment office, sits across the street from the Naval Support Activity Mid-South base. Navy officials ordered a lockdown during the tense minutes after the shooting, lifting it after word came that the gunman was in custody.

The station reports the wounded were identified as Major William J. Crawford and Sergeant Major Ricky R. McKenzie. Officials said they were expected to be released from a Memphis hospital soon. Millington Police Chief Rita Stanback said one victim was shot in the foot, the other in the leg.

All three of the men were recruiters, and the shooter has been in the Guard about six or seven years, said Navy spokesperson Maj. Gen. Max Haston.

Patton had reportedly been fired. He left, then returned with a gun, according to WREG.

Asked about the discipline the man had faced before the shooting, Haston would only say there were "administrative policies and procedures that we were going through with him."

The man was being held pending the filing of charges.

Stanback said Patton was apprehended by other National Guard members and he did not have the small handgun used in the shooting in his possession by the time officers arrived. 

There are more than 7,500 military, civilian and contract personnel working on the Navy base, according to its website. The facility is home to human resources operations and serves as headquarters to the Navy Personnel Command, Navy Recruiting Command, the Navy Manpower Analysis Center and the U.S. Army Corps of Engineers Finance Center.