A 17-year-old student has shot and critically wounded two fellow students at a high school in the US state of Maryland before dying after a gunfight with a campus security officer.
The shooting, which came amid a renewed national debate over gun violence following last month's Florida high school massacre, occurred just before 8am on Tuesday at Great Mills High School in St Mary's County, about 110km south of Washington.
The 16-year-old girl and a 14-year-old boy who were wounded were taken to hospital, county Sheriff Timothy Cameron said.
The girl was in intensive care with life-threatening critical injuries, while the boy was in good condition, the sheriff said.
The gunman was identified as Austin Wyatt Rollins, and Cameron said there was "an indication" of a prior relationship between him and the female student, though he added that was still under investigation.
The latest in a long string of deadly shootings at US schools and colleges took place a little more than a month after 17 students and educators were shot dead at Marjory Stoneman Douglas High School in Parkland, Florida.
That massacre sparked a new student movement against gun violence, including a national school walkout last week that included some Great Mills students.
It occurred just days before a planned Saturday march in Washington calling for new restrictions on guns.
"We recently had a protest about school violence last week, and now this has happened," said 16-year-old student Kameron Norwood, as he and other students who had been transported to another nearby high school waited to be picked up by relatives.
Sheriff Cameron said Rollins pulled out a Glock semiautomatic handgun in a hallway and shot the students.
The attack, which lasted less than a minute, ended after the school resource officer, Deputy 1st Class Sheriff Blaine Gaskill, ran inside the building and confronted Rollins, with both firing a single shot almost simultaneously.
The officer was not harmed, Cameron said. Rollins was confirmed dead after being taken to a hospital.
The incident appeared to be one of the only instances in which a school resource officer, typically a sworn law enforcement member, was able to intercede in the midst of an active shooting.
US President Donald Trump and the National Rifle Association have proposed arming teachers trained in firearms use to combat the threat of school shootings, while gun safety advocates have demanded a ban on semiautomatic rifles, among other laws.
More than 29,000 public schools in the United States, or roughly 30 per cent, reported having at least one full or part-time school resource officer in 2013, according to a 2015 survey by the National Center for Education Statistics.
Parkland students and Great Mills students exchanged supportive messages on Twitter following Tuesday's shooting.
"We are here for you, students of Great Mills, together we can stop this from ever happening again," tweeted Emma Gonzalez, a senior at Stoneman Douglas High School who survived last month's rampage.
Australian Associated Press
