A woman cries while embracing Texas Gov. Greg Abbott during a candlelight vigil held for the victims of a fatal shooting at the First Baptist Church of Sutherland Springs. Picture: Nick Wagner/Austin American-Statesman via AP

Washington - A lone gunman stormed into a small community church here on Sunday and shot and killed more than two dozen people before fleeing and later being found dead several miles from the scene, authorities said.

Witnesses said a white male in his 20s, dressed in all black and wearing a tactical vest, started shooting with an assault rifle as he approached the First Baptist Church in Sutherland Springs. 

Police say the gunman killed two people outside before entering the church and spraying bullets throughout the congregation during morning services in this countryside town about 30 miles southeast of San Antonio. 

"At this moment in time, there are 26 lives that have been lost," Texas Gov. Greg Abbott said during an early evening news conference. "We don't know if that number will rise or not, all we know is that's too many and this will be a long, suffering mourning for those in pain."

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Two law enforcement officials told The Washington Post that the suspect has been identified as Devin Kelley, 26, a Texas man who lived in a nearby county. Those officials did not see any immediate sign that he was motivated by international terror groups, but they cautioned that the investigation is still in its early stages.

Neighbours said they became aware of the shooting when they heard loud bangs - and even had bullets spray into their homes - shortly after 11 a.m. Sunday. Local authorities said the first calls of an active shooter came at about 11:20 a.m., after the gunman opened fire with a Ruger assault rifle.

Kevin Jordan, 30, was changing the oil in his Ford Focus ahead of a family road trip when he heard the pops of gunfire. When he stood up and turned his head, he saw a man wearing body armor, a vest and a mask walking down the sidewalk towards the church about 50 yards from his home.

"He was just spraying at the front of the church," Jordan said. "He was shooting outside at first and then he walked to the door and started shooting inside."

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Authorities said that at least 23 of the slain were killed inside the church, two people were shot and killed outside, and one additional person died at an area hospital. As the gunman exited the church, he was confronted by a local citizen who, armed with his own weapon, began firing - prompting the suspect to flee in his vehicle.

"The local citizen pursued him," said Freeman Martin, a regional director for the Texas Department of Public Service, who said the gunman crashed off of the roadway about 11 miles north of the shooting scene and was later found there, dead. "We don't know if it was a self-inflicted gunshot wound or if he was shot by our local resident who engaged him in a gunfight."

Authorities said they found multiple weapons in the gunman's vehicle.

After spotting the shooter, Jordan said he ran inside his home, scooped up his son and grabbed his wife and rushed his family inside his bathroom, where they crouched down and hid while calling 911. He said the shooter spotted him as he fled and took a shot that went though his front window, nearly hitting his 2-year-old son.

"I looked at the shooter and he looked right at me," he said. When the shooting stopped, Jordan, who works as a medical assistant, ran to the church, hoping to help.

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"I walked inside and just walked out - I couldn't handle it," he said. "It was bad. A lot of blood and bodies. The pews were knocked over. I'm a medical assistant and medical assisting does not prepare you for this."

Federal authorities, including from the Bureau of Alcohol, Tobacco, Firearms and Explosives and the FBI, were on the scene. The Texas Ranger Division of the state's Department of Public Safety also is involved in the investigation.

It came just more than a month after 58 people were killed at a Las Vegas country music festival, in what was the deadliest mass shooting in recent US history; the assailant, Stephen Paddock, killed himself after a lengthy shooting spree from his 32nd floor Mandalay Bay hotel suite.

Few details were immediately available about Kelley, and attempts to reach his family were unsuccessful Sunday. Kelley had at one point been in the military, enlisting in 2010 and serving as a logistical readiness airman stationed at Holloman Air Force Base in New Mexico, according to Air Force spokesperson Ann Stefanek.

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He was court-martialed in 2012 and sentenced to a year in military prison for assaulting his spouse and child, she said. He was reduced in rank and released with a bad conduct discharge in 2014.

It was unclear Sunday how Kelley obtained the weapon he used or why he targeted the church. Neighbours said the gunshots they heard were thundering.

Frank Pomeroy, the pastor of First Baptist Church, told ABC News that he was not present during the church service but that his teenage daughter, Annabelle Pomeroy, 14, was among the dead.

"She was very quiet, shy, always smiling, and helpful to all," Cynthia Rangel, 50, a resident of Stockdale, said of Annabelle Pomeroy. Rangel, a local emergency medical technician, said she knew three individuals who were hospitalized after the shooting and were undergoing surgery. "This just all seems like it's not real."

Dana Fletcher, who owns a business a quarter of a mile from the church, said she and her family just moved to Sutherland Springs. She said she was first alerted of the shooting after receiving a call from a reporter.

"My husband and I both are still in shock," she said. "It's a little tiny church that was targeted. It's shocking. It's a bit frightening because it's a little bit close to home."

President Donald Trump addressed the shooting while traveling in Asia on Sunday, sending his thoughts and prayers to the victims and families.

"This act of evil occurred as the victims and their families were in their place of sacred worship," Trump said. "We cannot put into words the pain and grief we all feel and we cannot begin to imagine the suffering of those who lost the ones they so dearly loved. Our hearts are broken but in dark times, and these are dark times, such as these, American do what they do best - we pull together. We join hands, we lock arms and through the tears and through the sadness we stand strong, oh so strong."

Carrie Matula, who works at a gas station near the church, told MSNBC that she ran out to see what was happening after hearing gunshots.

"I never thought it would happen here," she said. "This is something that happens in a big city. I would have never thought this would have taken place here. It's just too tight a community. It doesn't make sense."

Kathy Forton, 65, who has lived much of her life in the rural area of Wilson County, said the town has suffered an economic downturn since the county seat was moved to Floresville after a fire many years ago.

"The church helped out in so many ways, " Forton said. "Just the most precious loving people. The people from the church used their own money to provide turkeys for the community at Thanksgiving, and presents for kids at Christmas. The loss of these people is going to devastate that community."