At least 26 people were killed after a gunman opened fire inside a church in Sutherland Springs town of Texas in the United States during Sunday service, Reuters reported. The casualties were 5 to 72 years old, authorities said.

Around 20 people were injured in the attack at the First Baptist Church in the town, around 65 km east of San Antonio, around 11.20 am, ABC News reported.

The suspect, wearing a ballistic vest, opened fire at the church, before a local resident confronted him with a gun. He then fled the scene in his car and was found dead in Guadeloupe County. Officials are not sure whether the suspect killed himself or was shot dead in a gunfire.

The gunman was identified as 26-year-old Devin P Kelly, unidentified policemen told The New York Times. In a statement, the Pentagon said the gunman had served as an airman “at one point”, The Guardian reported. However, the agency did not give any further details about his time in the Air Force. Reports said multiple weapons were found in his vehicle.

“We are dealing with the largest mass shooting in our state’s history,” Texas Governor Greg Abbott said during a press conference. “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.”

Teams from the Federal Bureau of Investigation, the Texas Rangers, and the Bureau of Alcohol, Tobacco and Firearms and Explosives are investigating the attack. US President Donald Trump, who is currently in Japan as part of his Asia tour, said he was monitoring the situation.