The unidentified shooter walked into the First Baptist Church of Sutherland Springs just before noon and began firing, authorities said.
Wilson County Commissioner Albert Gamez, Jr. told CNN that first-responders informed him the death toll is at 26 — and expected to climb.
“My heart is broken,” he said. “We never think where it can happen, and it does happen. It doesn’t matter where you’re at. In a small community, real quiet and everything, and look at this, what can happen.”
The gunman fled in a vehicle, but cops caught up with him after a short chase, according to Gamez, who told CNN it was unclear whether cops killed the gunman or he turned the weapon on himself.
Investigators are now searching for video that could shed more light on what happened.
The town — population about 400 — is roughly 30 miles southeast of San Antonio.
The violence comes just a month after the US’s worst-ever mass shooting — when madman Stephen Paddock opened fire on an outdoor Las Vegas concert on Oct. 1, killing 58 and injuring hundreds.