At least two people are dead in a shooting at a military base in San Antonio, Texas, authorities said.

The attack appears to be a murder-suicide, Bexar County Sheriff’s Office spokesman James Keith told MSNBC.

The base’s public affairs unit said only that there was an announcement for people on the base to close doors and turn off lights.

Sydney Spalding was heading towards the graduation field to see a friend graduate from the Air Force when the base went under lockdown.