A primary school shooting in the US state of Texas has left at least 18 students and one teacher dead.
Texas Governor Greg Abbott confirmed the shooter, an 18-year-old male, was also killed as a result of police intervention at the school in Uvalde, CNN reported.
Police said the victims were believed to be students either in the second, third or fourth grade at Robb Elementary, who are typically aged between 7 and 10 in the US.
Texas State Senator Roland Gutierrez updated the death toll from 15 to 21 on Tuesday evening.
Multiple students have also been rushed to a nearby hospital with gunshot injuries, ABC News reported.
"He shot and killed horrifically and incomprehensibly 14 students and killed a teacher," Mr Abbott said.
Mr Abbott identified the gunman as Salvador Ramos. He was believed to have been in possession of a handgun and a rifle. CNN reported he drove up to the school on Tuesday morning (local time).
Ramos is believed to have acted alone, Pete Arredondo, chief of the Uvalde Consolidated Independent School District Police Department, said.
Romas, who was a high school senior in Uvalde, allegedly shot dead his grandmother before entering the school grounds, police said according to KHOU. She is "holding on" in hospital, Mr Gutierrez said, contradicting earlier reports she had been killed.
"When parents drop their kids off at school, they have every expectation to know that they're going to be able to pick their child up when that school day ends. And there are families who are in mourning right now," Mr Abbott said.
Two officers were injured responding to the shooting, however did not sustain life-threatening injuries.
The shooting comes in the same month a teen shot dead 10 people at a New York state supermarket in what authorities say was a "racially motivated" attack.
The shooting in Texas was one of the deadliest at a US school since a gunman killed 26 people, including 20 children, in a rampage at Sandy Hook Elementary School in Connecticut in December 2012.
'This only happens in this country', senator bemoans
Houston Mayor Sylvester Turner said the shooting had left him "heartbroken".
“How many more children must lose their lives from senseless gun violence?" he asked, calling for tighter gun control laws.
Democratic Senator Chris Murphy delivered a passionate plea on the floor of the Senate in the wake of the shooting, calling for action.
"Our kids are living in fear every single time they set foot in a classroom because they think they're going to be next. What are we doing?" he asked.
"This only happens in this country, and nowhere else."
Do you have a story tip? Email: firstname.lastname@example.org.