At least 15 people have been killed in a shooting at a Texas elementary school.

This was confirmed by Texas Governor Greg Abbott.

These are 14 children and a teacher.

The attacker was also dead, the governor said.

He was probably shot by police officers.

Other children were injured, the US broadcasters ABC and CNN reported on Tuesday.

They are treated in hospitals.

At a news conference, Abbott said the shooter was an 18-year-old man who exited his vehicle and entered the school with a handgun and possibly a rifle.

"He shot 14 students and killed a teacher in a horrific and incomprehensible manner," Abbott said.

The suspect is also said to have shot his grandmother before entering the school and opening fire again.

He gave no further information about her condition.

Police officers also injured

Uvalde Memorial Hospital said 15 injured were treated in the hospital's emergency department after the incident.

University Hospital San Antonio said it was also treating two patients from the incident -- a child and an adult.

Two police officers are among the injured.

It is expected that they will survive.

Earlier, Uvalde School District said a gunman was staying at Robb Elementary School and asked the public to stay away from the area.

"There is an active shooter at Robb Elementary School," the school district wrote on Twitter.

"Law enforcement is on site.

We ask for your help and ask you not to enter the school grounds.

As soon as we have more information, we will pass it on."

A school official initially told ABC News that the shots were fired outside of campus and Robb Elementary School was under lockdown at the time.

The incident happened at an elementary school in the city of Uvalde, about 135 kilometers west of San Antonio.

Uvalde is a town with around 16,000 inhabitants.

Deadly gun attacks are common in the United States.

Schools are also often affected.