An 18-year-old gunman opened fire on Tuesday at a Texas elementary school, killing at least 19 children as he went from classroom to classroom, officials said, in the deadliest school shooting in nearly a decade and the latest gruesome moment for a country scarred by a string of massacres.

The attacker was killed by law enforcement.

The death toll also included two adults, authorities said. Governor Greg Abbott said one of the two was a teacher.

The assault at Robb Elementary School in the heavily Latino town of Uvalde was the deadliest shooting at a US grade school since a gunman killed 20 children and six adults at Sandy Hook Elementary in Newtown, Connecticut, in December 2012.

Hours after the attack, families were still awaiting word on their children.

Outside the town civic centre, where families were told to gather, the silence was broken repeatedly by screams and wailing. “No! Please, no!” one man yelled as he embraced another man.

The school district superintendent, Hal Harrell, said, “My heart is broken today” and announced that all school activities were cancelled for the time being. “We’re a small community, and we’re going to need your prayers to get through this.”

The attack also came just 10 days after a deadly, racist rampage at a Buffalo, New York, supermarket that added to a years-long series of mass killings at churches, schools and stores. And the prospects for any reform of the nation’s gun regulations seemed as dim, if not dimmer, than in the aftermath of the Sandy Hook deaths.

But US President Joe Biden appeared ready for a fight, calling for new gun restrictions in an address to the nation hours after the attack.

“As a nation we have to ask, when in God’s name are we going to stand up to the gun lobby? When in God’s name are we going to do what has to be done?” Biden asked. “Why are we willing to live with this carnage?”

Many of the wounded were rushed to Uvalde Memorial Hospital, where staff members in scrubs and devastated victims’ relatives could be seen weeping as they walked out of the complex.

'Shooter acted alone'

Officials did not immediately reveal a motive, but they identified the assailant as Salvador Ramos, a resident of the community about 135 kilometers west of San Antonio. Law enforcement officials said he acted alone.

Ramos had hinted on social media that an attack could be coming, according to state Senator Roland Gutierrez, who said he had been briefed by state police. He noted that the gunman “suggested the kids should watch out”.

Before heading to the school, Ramon killed his grandmother with two military-style rifles he purchased on his birthday, Gutierrez said.

“That was the first thing he did on his 18th birthday,” he said.

The attack began about 11:30am, when the gunman crashed his car outside the school and ran into the building, according to Travis Considine, a spokesman for the Texas Department of Public Safety. A resident who heard the crash called 911, and two local police officers exchanged gunfire with the shooter.

Both officers were shot, though it was not immediately clear where on the campus that confrontation occurred, or how much time elapsed before more authorities arrived on the scene.

Meanwhile, teams of Border Patrol agents raced to the school, including 10 to 15 members of a Swat-like tactical and counter-terrorism unit, said Jason Owens, a top regional official with the Border Patrol.

One Border Patrol agent who was working nearby when the shooting began rushed into the school without waiting for backup and shot and killed the gunman, who was behind a barricade, according to a law enforcement official speaking on condition of anonymity because he was not authorised to talk about it.

The agent was wounded but able to walk out of the school, the law enforcement source said.

Owens confirmed that an agent suffered minor injuries, but would not provide details of that confrontation.

He said some area agents have children at Robb Elementary.

“We have Border Patrol kids that go to this school. It hit home for everybody,” he said.

It was not immediately clear how many people were wounded, but Uvalde Police Chief Pete Arredondo said there were “several injuries”. Earlier, Uvalde Memorial Hospital said 13 children were taken there. Another hospital reported a 66-year-old woman was in critical condition.

Robb Elementary School has an enrollment of just under 600 students, and Arredondo said it serves students in the second, third and fourth grade. He did not provide ages of the children who were shot. This was the school’s last week of classes before summer break.

Uvalde, home to about 16,000 people, is about 120 kilometers from the border with Mexico. Robb Elementary is in a mostly residential neighbourhood of modest homes.

Deadliest school shooting in Texas history

The tragedy in Uvalde was the deadliest school shooting in Texas history, and it added to a grim tally in the state, which has been the site of some of the deadliest shootings in the US over the past five years.

In 2018, a gunman fatally shot 10 people at Santa Fe High School in the Houston area. A year before that, a gunman at a Texas church killed more than two dozen people during a Sunday service in the small town of Sutherland Springs. In 2019, another gunman at a Walmart in El Paso killed 23 people in a racist attack.

The shooting came days before the National Rifle Association (NRA) annual convention was set to begin in Houston. Abbott and both of Texas’ US senators were among elected Republican officials who were the scheduled speakers at a Friday leadership forum sponsored by the NRA’s lobbying arm.

In the years since Sandy Hook, the gun control debate in Congress has waxed and waned. Efforts by lawmakers to change US gun policies in any significant way have consistently faced roadblocks from Republicans and the influence of outside groups such as the NRA.

A year after Sandy Hook, Senators Joe Manchin, a West Virginia Democrat, and Patrick J. Toomey, a Pennsylvania Republican, negotiated a bipartisan proposal to expand the nation’s background check system. But the measure failed in a Senate vote, without enough support to clear a 60-vote filibuster hurdle.

Then-president Barack Obama, who had made gun control central to his administration’s goals after the Newtown shooting, called Congress’ failure to act “a pretty shameful day for Washington”.

Last year, the House passed two bills to expand background checks on firearms purchases. One bill would have closed a loophole for private and online sales. The other would have extended the background check review period. Both languished in the 50-50 Senate, where Democrats need at least 10 Republican votes to overcome objections from a filibuster.