“The teacher was just lying there and he was limp,” he told KOLO. “And me and five other friends went to him and said come on we’ve got to get him to safety. We picked him up, carried him a little bit far and we left him because our vice principal came along and said go, go, go get to safety, get to safety. So we left the teacher there and we went to safety.”

The incident marked the latest in a string of shooting rampages across the United States in recent years, including a shooting last December at a Connecticut elementary school that killed 20 students and six adults and helped reignite a national debate over gun control.

Also on Monday, a man who wanted his money back after paying to enter a Las Vegas nightclub shot three people, killing one, when the club management refused to make a refund, police said.

The suspect, later identified as Benjamin Frazier, 41, was wounded when several patrons and club employees wrestled him to the ground during a resulting melee, police said. Frazier was hospitalised early on Monday but will be taken into custody as soon as he is released, said Jose Hernandez, an officer with the Las Vegas Metropolitan Police Department.

Video: Police lockdown school and evacuate children, investigation begins

The slain educator in the Sparks Middle School shooting was identified by his family as 45-year-old math teacher Michael Landsberry.

Authorities declined to identify the two wounded students, both age 12, who acting Sparks Police Chief Tom Miller said were rushed to a Reno hospital where one had emergency surgery.

One of the boys sustained a gunshot wound to the shoulder and the other was hit in the abdomen, he said, and were listed in stable condition on Monday afternoon.

Teacher called hero

Family members of Landsberry, a former Marine who was also a member of the Nevada Air National Guard, described him as a hero who tried to persuade the young gunman to drop his weapon.

“(He was) probably trying to stop that kid from hurting himself or anyone else,” his sister-in-law Chanda Landsberry said.

Law enforcement officials said the student gunman opened fire with a semi-automatic handgun at 7.16am local time, about 15 minutes before classes were scheduled to begin at the school, which serves about 700 seventh and eighth grade students.

A 13-year-old eighth grader, Kyle Nucum, told the Reno Gazette-Journal newspaper that he heard about half a dozen shots. Student Michelle Hernandez said she had seen the suspect before the shooting began.

“I heard him saying, ’Why you people making fun of me, why you laughing at me,’” Hernandez told the paper.

The 12-year-old shooter was not identified by authorities.

Some 150 to 200 police officers descended on the school following the shooting and searched the grounds with bomb dogs, Reno Deputy Police Chief Tom Robinson said. Agents from the FBI and US Department of Homeland Security were assisting in the investigation, he said.

Sparks Mayor Geno Martini told a late-morning news conference that the shooting marked a tragic day for the city: ”I just want to reiterate again that the city itself is very safe and this is just an isolated incident. But it’s very, very tragic.”

Robinson said it was too early to tell if the boy was targeting anyone in the shooting rampage. Authorities also declined to immediately speculate on his motives.

Classes and after-school activities were cancelled at Sparks Middle School for the rest of the week and counsellors would be on hand to work with students and staff members who were traumatised by the shooting, the school district said.