Maryland school shooting: Two students fighting for life and gunman killed after opening fire at Great Mills High School

Two students are fighting for life and a teenage gunman was killed after he opened fire inside a US high school.

The shooting took place at Great Mills High School in St Mary's County, Maryland, on Tuesday morning.

The shooter, who was also a student at the school, was shot by a campus policeman, St Mary's County Tim Cameron confirmed, but it wasn't known if the officer's bullet killed the suspect.

A police spokeswoman confirmed the shooter and two victims, a male and female student, were all taken to hospital in a critical condition. The shooter later died.

A school security officer is believed to have ended the attack when he shot the gunman, who is also understood to be a pupil.

Mollie Davis, a student at the school, tweeted: "There was a loud sound and everyone started screaming and running."

She said: "I am in Great Mills HS. My school is on a very real lockdown threat and there’s already someone possibly dead. Please pray for us."

She added later: "You never think it’ll be your school and then it is. Great Mills is a wonderful school and somewhere I am proud to go. Why us?"

Jonathan Freese, another student at Great Mills, spoke to CNN while he was in lockdown in his maths class.

He said police were going through classrooms to clear the school and students would then be escorted out of the school.

"I'm still a little shaken up," he added.

The school, which is attended by about 1,600 students, was placed on lockdown and the incident was "contained".

St. Mary's County Public Schools tweeted: “There has been a Shooting at Great Mills High School.

“The school is on lock down the event is contained, the Sheriff's office is on the scene additional information to follow.”

Local police warned parents to stay away from the school.

The sheriff's office said on Twitter: "There has been an incident at Great Mills High School. Parents please DO NOT respond to the school."

Maryland Governor Larry Hogan said: “We are closely monitoring the situation at Great Mills High School. @MDSP is in touch with local law enforcement and ready to provide support.

“Our prayers are with students, school personnel, and first responders.”

Congressman Steny Hoyer added: "I’m closely monitoring reports of an incident at Great Mills High School in St. Mary’s County. My prayers are with the students, parents, and teachers."

It comes just over a month after 17 students were killed by a gunman at Marjory Stoneman Douglas High School in Florida, reigniting the national debate in the US on gun control.

Great Mills is a town about 70 miles south of Washington.