At least 20 people killed in shooting at Texas church

At least 20 people have been killed in a church shooting in Sutherland Springs, Texas, according to Wilson County Sheriff Joe Tackitt.

Many more have been injured, authorities said Sunday.

The shooter was killed after a brief chase north into neighboring Guadalupe County, according to Guadalupe County Sheriff's Office spokesman Robert Murphy. It is unclear if the shooter was killed by police or took his own life, Murphy said.

The FBI is responding to the scene of the shooting, according to Michelle Lee, spokeswoman for the FBI's San Antonio field office.

Local police also have responded to the scene, which occurred at the First Baptist Church, a witness told CNN. The witness, a cashier at a gas station across the street from the church, said she heard about 20 shots being fired in quick succession while a church service was underway around 11:30 a.m. local time.

Sutherland Springs is in Wilson County, about 30 miles east of San Antonio.

Wilson County Commissioner Albert Gamez Jr. told CNN that multiple people were killed and numerous people were injured in Sunday's shooting.

"My heart is broken," Gamez 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."

A law enforcement source told CNN that a man walked into the church and began shooting about 11:30 a.m. local time. Agents from the San Antonio field office of the Bureau of Alcohol, Tobacco, Firearms and Explosives are en route to the scene, the source said.