State Governor Greg Abbott said the suspect, an 18-year-old local man who has also died, opened fire at Robb Elementary School in Uvalde, about 137 kilometres west of San Antonio.

“He shot and killed, horrifically, incomprehensibly, 14 students and killed a teacher,” the governor said.

The gunman was a resident of the community and entered the school with a handgun, and possibly a rifle, and opened fire, Abbott said.

He said the shooter was probably killed by responding officers but events were still being investigated.

Uvalde Memorial Hospital said earlier 13 children were taken by ambulance or bus to that facility, and another hospital reported a 66-year-old woman was in critical condition.

It was not immediately clear how many people, in addition to the dead, were injured in the shooting

Earlier, the Uvalde Consolidated Independent School District had said an active shooter was reported at the school, which caters for about 600 students.

A heavy police presence surrounded the school on Tuesday afternoon, with officers in heavy vests diverting traffic and FBI agents coming and going from the building.

The district said the city’s civic centre was being used as a reunification location.

The shooting in Texas came less than two weeks after a gunman opened fire at a supermarket in Buffalo, New York, killing 10 Black shoppers and workers in what officials have described as a hate crime.

Uvalde is home to about 16,000 people and is the seat of government for Uvalde County.

The town is about 120km from the border with Mexico, with the school in a mostly residential neighbourhood of modest homes.

 – AAP