The bodies of two men were found inside a room
US police say two people have died in an apparent murder-suicide at Lackland Air Force Base in San Antonio, Texas.
"It's over," said Bexar County sheriff's spokesman James Keith as a lockdown was lifted after two hours at the facility.
Officials said the bodies of two males were found inside a room at Forbes Hall in the Medina Annex on base.
Brig Gen Robert Labrutta told a news conference two firearms were found near the bodies. It is not clear who owned the weapons.
The FBI said it had been called to help the investigation and determined it was not an act of terrorism.
Police said they would name the deceased once next-of-kin had been informed.
The commanding officer of the 331st K-9 Training Squadron at the base was shot by an airman, according to initial internal Pentagon communications cited by the Air Force Times.
Shortly before news broke of the shooting at 8:40am on Friday, Lackland base said in a tweet that it had a basic military training graduation event scheduled for Friday.
Authorities posted a warning on the Joint Base San Antonio Facebook page which said: "There is a real world active shooter situation at Joint Base San Antonio-Lackland Medina Annex and base and local authorities are on the scene at this time".
The sprawling base, which is the home of Air Force basic training, has a population of around 10,000 people, including three schools.
Fort Hood in Texas was the site of the deadliest shooting at a US military base, when 13 people killed and 31 injured in 2009.