Police in Texas said that at least two people were killed Friday in a shooting at an Air Force base. Authorities said that it appeared the situation at the Lackland part of Joint Base San Antonio-Lackland was a murder-suicide, but they cautioned that officials were still searching locked rooms to see if there are possible other victims or shooters.

“It appears to be a murder-suicide,” James Keith, spokesman for the Bexar County Sheriff’s Office, said in a telephone interview Friday. “We have sheriff’s deputies inside, currently looking for other victims and any other possible shooters.”

While police believe one of the two people killed was the shooter, “we are not ready to confirm that,” Keith said. Deputies were checking several other locked rooms in a facility at Lackland on Friday to see if they can find any other people related to the shooting, he said.

Keith said police did not have any information about any possible motive or a relationship between the two people who were killed. Another law enforcement official who spoke on the condition of anonymity said that the incident appears to have emanated from a dispute.

The Air Force Times reported Friday that an internal memo said the commanding officer of a training squadron at the base was shot by an airman.

Police were called Friday morning about reports of an active shooter at Lackland, which prompted a lockdown at the joint base.

The FBI said it was assisting in the investigation Friday. Ann Stefanek, an Air Force spokeswoman at the Pentagon, said the service’s security forces as well as local law enforcement responded to the shooting.

The shooting was reported at the Medina Training Annex, which is west of the main part of the base and the city of San Antonio, Stefanek said. This annex is outside Interstate 410, the highway ringing San Antonio.

This annex was once used to train Air Force officers, but is now set aside for the training of military police, Air Force Special Operations forces who work in special tactics and other personnel. Military police regularly use the annex for training, based on photos released by the Air Force.