Wilson County Commissioner Albert Gamez Jr told CNN that at least 27 people have been killed in the shooting, but the death toll is expected to climb. He killed at least 25 people at First Baptist Church on Sunday morning and injured at least as many more. He entered the church at 11:30 AM local time, reports claim.
The shooting comes just over a month after a gunman in Las Vegas, firing down from a hotel room, killed 58 people and wounded hundreds attending an outdoor concert.
The FBI is heading to the scene, ABC News has learned.
Police say that Kelley was shot after a auto chase with officers. The FBI & law enforcement are on the scene.
He tweeted: "May God be w/ the people of Sutherland Springs, Texas".
One of the victims of the mass shooting was the church's pastor Frank Pomeroy's daughter, Annabelle. "I am monitoring the situation from Japan", Trump wrote on Twitter.
A spokeswoman say the federal Bureau of Alcohol, Tobacco, Firearms and Explosives is sending special agents from field offices in Houston and San Antonio to the site of a church shooting in South Texas.
"We heard several shots and we all started running inside the store", said the woman, who said she is 49 but declined to give her name. The people of Sutherland Springs need our prayers right now.
Sutherland Springs is 30 miles (48 kilometers) southeast of San Antonio.
Contacted by Al Jazeera, the Wilson County sheriff was not immediately available for comment.
A number of helicopters have arrived to transport the wounded, KSAT 12 reporter Max Massey said.