Texas authorities said two people were killed Friday at an air force base in San Antonio.
"Right now it does appear to be a murder-suicide situation," Bexar County Sheriff's Office spokesman James Keith said.
The commanding officer of the 331st K-9 Training Squadron at Joint Base San Antonio-Lackland was shot by an airman, according to the Air Force Times, an independent news outlet, citing internal Pentagon communications.
Neither person was immediately identified.
The Bexar County Sheriff's department and San Antonio police responded to reports of a shooter shortly before 9 a.m. local time Friday at the base.
Keith said two bodies were found inside a room of a building on base. However, sheriff's deputies and other law enforcement officers continued to search the building and nearby facilities.
A lockdown of the base was lifted late Friday morning.
The facility is a key training installation for the U.S. Air Force. The shooting took place at the base's Medina annex, where dog training takes place.
In 2009, Fort Hood, which is about 260 kilometers (160 miles) from Joint Base San Antonio-Lackland, was the site of the deadliest shooting at a U.S. military base, when Major Nidal Hasan shot to death 13 people and wounded 31 others.
Hasan, who was shot by a civilian police officer during the incident, was convicted and sentenced to death in 2013.
Some material for this report came from AP and Reuters.
