Two people were killed outside the First Baptist Church in Sutherland Springs in Wilson County, about 65 kilometres east of San Antonio, around 11.20am on Sunday local time before the shooter entered the church and opened fire during a sermon.
Twenty three bodies were found inside the church and another died in hospital. Their ages ranged from five to 72.
Twenty others have been taken to hospital with severe to minor injuries.
After the shooting, the gunman, named in media reports as 26-year-old Devin Patrick Kelley, was fired on by a local resident before fleeing in his vehicle. He was later found dead in his car, along with other weapons, in neighbouring Guadalupe County.
It was not immediately clear if the gunman killed himself or he was hit by gunfire by the resident, authorities say. A motive for the shootings has also not been disclosed by authorities.
“We are dealing with the largest mass shooting in our state’s history,” Texas Governor Greg Abbott said at the news conference on Sunday.
“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.”
Texas Department of Public Safety regional director, Freeman Martin, said the gunman was armed with a Ruger AR assault rifle, and dressed in black, tactical gear and a ballistic vest.
Martin said the gunman started firing at the church as he crossed the street from his car. He then entered the church and continued to fire.
“As he exited, a local resident engaged him and he dropped his weapon. He fled from the church,” Freeman said.
The 14-year-old daughter of pastor Frank Pomeroy was killed, the family told several television stations.
Jeff Forrest, a 36-year-old military veteran who lives a block away from the church, said what sounded like high-calibre, semi-automatic gunfire triggered memories of his four combat deployments with the Marine Corps.
“I was on the porch, I heard 10 rounds go off and then my ears just started ringing,” Forrest said. “I hit the deck and I just lay there.”
The massacre comes just weeks after a sniper killed 58 people at an outdoor concert in Las Vegas, the deadliest mass shooting in modern US history. The shootings have stirred a years-long national debate over whether easy access to firearms was contributing to the trend.
US President Donald Trump said he was monitoring the situation while in Japan on a 12-day Asian trip and has described the shootings as an “act of evil” as victims and their families were at their place of “sacred worship”.
“May God be w/ the people of Sutherland Springs, Texas. The FBI & law enforcement are on the scene,” he said on Twitter.
Trump says he’s has spoken with Governor Abbott and says the state of Texas has the administration’s “full support”.
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