SUTHERLAND SPRINGS, US (NDTV): A gunman went into a Baptist church in Texas during Sunday morning services and shot dead some two dozen worshippers, the sheriff said, in the latest mass shooting to shock the United States.

A total of 26 people were killed during the gunman's shooting rampage at a Texas church during Sunday services, Governor Greg Abbott said, warning the toll may rise.

"We are dealing with the largest mass shooting in our state's history. There's so many families who have lost family members. Fathers, mothers, sons and daughters," Abbott said.

"The tragedy, of course, is worsened by the fact that it occurred in a church, a place of worship, where these people were innocently gunned down. We mourn their loss, but we support their family members."

Exactly five weeks after the worst shooting in modern US history, the latest tragedy prompted an outpouring of condolences, led by US President Donald Trump.

The worshippers were gunned down at First Baptist Church in Sutherland Springs, a small rural community about 50 kilometers southeast of San Antonio.

With details rapidly unfolding, some unnamed officials were quoted as citing tolls as high as 27 dead and 20 or more wounded.

The gunman reportedly walked into the church shortly before noon -- at a morning service that witnesses said was normally attended by some 50 people -- and opened fire.

The dead included the 14-year-old daughter of pastor Frank Pomeroy, the church leader told ABC News.