Nineteen children and two adults have been confirmed dead in a shooting at a primary school in south Texas, of the United States Tuesday night.

The gunman opened fire on Robb Elementary School, where young children aged seven to 10 are being taught, in the city of Uvalde before he was killed by law enforcement, officials said.

Accoding to a BBC report, investigators say the 18-year-old suspect had a handgun, an AR-15 semi-automatic rifle and high-capacity magazines.

The teenager is suspected of shooting his grandmother before the rampage and local media report he may have been a high school student in the area.

Uvalde Consolidated Independent School District Chief of Police Pete Arredondo said the shooting began at 11:32 local time on Tuesday, and that investigators believe the attacker “did act alone during this heinous crime”.

Texas Governor Greg Abbott said the shooter, whom he named as Salvador Ramos, abandoned a vehicle before entering the school to “horrifically, incomprehensibly” open fire.

One of the adults killed was a teacher, who has been named in the US media as Eva Mireles. Her page on the school district’s website said she has a daughter in college and loved running and hiking.

Nearly 500 pupils are enrolled in the predominantly Hispanic school around 85 miles (135km) west of the city of San Antonio.

The Associated Press news agency reports that a US Border Patrol official who was nearby when the shooting began rushed into the school and shot and killed the gunman, who was behind a barricade.

Border Patrol is a federal agency that guards US ports of entry. Uvalde, which is fewer than 80 miles from the border with Mexico, is home to a Border Patrol station.

Two border agents were reportedly shot in an exchange with the gunman. One agent was shot in the head, officials say, adding that both were now in a stable condition in hospital.

According to CBS News, the attacker was wearing body armour as he carried out the attack. Another 18-year-old who is suspected of attacking a grocery store in Buffalo, New York, on 14 May was also wearing body armour and carrying a semi-automatic rifle – both of which are commercially available in the US.

The Uvalde Memorial Hospital posted on Facebook earlier that 13 children had been taken to hospital “via ambulances or buses”.

A 66-year-old woman and a 10-year-old girl were in a critical condition at a hospital in San Antonio, University Health hospital officials said.

There have already been 27 school shootings this year alone. Young school children routinely rehearse what to do if a gunman enters their classroom.

It’s only 10 days since ten people were killed in a mass shooting in New York.

Politicians recognise this a problem almost unique to America, where guns have overtaken car crashes as the leading cause of death for children and teenagers. But it’s a problem that politics seem incapable of solving. Deeply entrenched views on gun control are not changed in response to events like the tragedy in Uvalde.

“Why do we keep letting this happen?” asked President Biden. “Why are we willing to live with this carnage?”

But there is no sign that Democrats will get any closer to passing tighter gun control legislation. Some Republicans are already accusing of them of using this latest school shooting to cynically further their own political objectives.

Robb Elementary School will join the roll call of school shootings along with Sandy Hook and the Parkland shooting. The killing of innocent schoolchildren has reignited the debate over guns in America, but has not brought it any closer to a resolution.

As evening fell police remained outside the community centre in Uvalde braving an intense rainstorm.

Earlier, cries and sobs could be heard from outside as family members who gathered there received the devastating news that their children had been killed.

Others were asked to give DNA samples to help identify some of the young victims.

Just a few blocks from the Robb Elementary school, a small vigil was held for the victims and survivors of the attack.

Karla Bohman’s voice cracked as she told the group about a family friend whose young daughter, a student at the school, was among those still unaccounted for.

“They don’t know if she’s in surgery or one of the fatalities, but they know she’s a victim of some sort because she’s missing,” Bohman cried. “I can’t believe this.”

Cheryl Juhasz, a lifelong resident of Uvalde, quietly wept during the prayer.

“You can’t comprehend evil like this. No matter where it happens, but it’s harder when it happens at home.”

School district superintendent Hal Harrell said the school year had been ended early in the wake of the shooting.

In a speech from the White House, US President Joe Biden said he was “sick and tired” of responding to mass shootings, as he called for gun control.

“How many scores of little children who witnessed what happened – see their friends die, as if they’re in a battlefield, for God’s sake,” he said. “They’ll live with it the rest of their lives.”

He ordered that flags at the White House and other US federal buildings be flown at half-mast in honour of the victims in Uvalde.

School shootings have become recurring emergencies in the US, with 26 recorded last year, according to EdWeek, an education trade publication.