Texas school massacre: 18 children, 3 adults shot dead, several critical

In one of the worst school shootings in American history, an 18-year-old gunman has killed 21 people, including 18 children, and rendered several other grievously injured at an elementary school in Texas state, before the assailant was eliminated in police firing.

Gunshots rang out of Robb Elementary School in Uvalde town, Texas, 134 km from San Antonio, at about 11.30 AM on Tuesday.

Texas Governor Greg Abbott identified the killer as Salvador Ramos, a resident of the area where the school was located. The shooter's motive remains unclear.

"He shot and killed horrifically, incomprehensibly. Fourteen students and a teacher killed," Abbott said in the evening; later the toll was raised to 18 children and three adults dead.

Two law enforcement officers were shot but are expected to recover, Abbott said.

Ramos was armed with a handgun and an AR-15 semiautomatic rifle, law enforcement sources confirmed.

The shooter also carried high-capacity ammunition magazines.

Names of the deceased and other details were yet to be released. According to the school website, its students are aged between 5 years and 11 years.

The deceased children are in the second, third and fourth grades - aged between 7 years and 10 years, he said.

US President Joe Biden was briefed on the shooting during his return flight from Japan where he attended the Quad Summit.

Biden will address the media on the shooting in the evening after he returns to Washington, his Press Secretary Karine Jean-Pierre said.

Biden has ordered the US flag to be flown at half-mast until sunset on Saturday May 28, in memory of those killed in Texas.

The US flag across all public buildings, grounds, military posts, naval stations, naval vessels, embassies, consular offices and military facilities will be in half-mast.

In Uvalde, all schools were locked once the gunshots were heard.

In addition to the confirmed deaths, a number of people have been injured. No number on the injured has been released.

Texans across the state grieved for the victims.

Officials said the city's civic center was being used as a reunification center where the kin of victims can procure information from the state and coordinate other functions.

The South Texas Blood and Tissue Center issued a public appeal for blood donations. They have already sent over 15 units of blood and are running out.

There is currently a blood shortage at the local hospitals where the wounded are being treated.

Emergency blood donation appointments are being held for Wednesday.

The shooting stoked the fiery debate on guns control.

Texas Attorney General Ken Paxton said teachers should be armed to stop such incidents in the future.