Deputies says a student pulled out a gun and shot two other students at a high school in southeast Maryland Tuesday morning. The shooter exchanged fire with a trained, armed deputy sheriff who was in the school as a school resource officer. The SRO killed the shooter.

THE LATEST:

A student pulled out a gun and shot two other students at a high school in southeast Maryland Tuesday morning before the shooter was killed, the St. Mary’s County sheriff says.

The gunman entered Great Mills High School in Great Mills at the beginning of the school day and shot a female student in a hallway, Sheriff Tim Cameron told NBC Washington. A male student also was hit by a bullet.

Two students are in critical condition, and the shooter was pronounced dead later Tuesday morning.

Information was not available immediately on the relationship between the students, Cameron said. A motive is not yet clear.

The shooter exchanged fire with a school resource officer, a trained, armed deputy sheriff, Cameron said. The shooter was wounded; the officer was not.

EARLIER:

Deputies were called to the school about 60 miles southeast of Washington, D.C. just before 8 a.m.

A student pulled a gun out and shot two other students at a high school in southeast Maryland Tuesday morning before he was wounded himself, the St. Mary’s County sheriff said.

The gunman entered Great Mills High School in Great Mills, Maryland, at the beginning of the school day and opened fire, Sheriff Tim Cameron said. A teenage girl and boy were injured in the shooting.

The shooter exchanged fire with a school resource officer on campus and was wounded, Cameron said. All three students are in critical condition, but the officer wasn’t injured. It wasn’t yet clear who shot the gunman.

The school is locked down and the incident has been contained, according to the the website of Great Mills High School in Great Mills, Maryland. The school didn't give further information.

Deputies were called to the school just before 8 a.m. The school is located about 60 miles southeast of Washington, D.C.

A Twitter post from the St. Mary's County Sheriff's Office asked parents not to report to the school due to the incident, but to go to a high school in nearby Leonardtown instead.

Agents of the were Bureau of Alcohol, Tobacco, Firearms and Explosives were traveling to the school to assist with the investigation.

Maryland Gov. Larry Hogan said in a tweet Tuesday that he is "closely monitoring the situation."

"Our prayers are with students, school personnel, and first responders," Hogan said.

President Donald Trump was made aware of the shooting and the White House is monitoring the incident, press secretary Sarah Huckabee Sanders said on Fox News.

The shooting comes four days before the national March for Our Lives, a rally for student safety inspired by last month’s massacre at Marjory Stoneman Douglas High School in Parkland, Florida.

"We are here for you, students of Great Mills," Parkland student activist Emma Gonzalez tweeted, "together we can stop this from ever happening again."

UPDATE:

The Latest: FBI agents at Maryland school after shooting

GREAT MILLS, Md. (AP) — The Latest on the shooting at a Maryland high school (all times local):

10 a.m.

FBI agents are on the scene of a shooting at a high school in southern Maryland.

FBI spokesman David Fitz says the agents are there to assist the local sheriff's office and he had no immediate information about injuries or fatalities at Great Mills High School.

Agents from the federal Bureau of Alcohol, Tobacco, Firearms and Explosives have also been sent to the school.

The county sheriff said deputies are on the scene and that parents or guardians should stay away, going instead to Leonardtown High School to reunite with Great Mills students there.

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9:30 a.m.

A sheriff's spokeswoman says injuries have been reported after a shooting at a high school in southern Maryland.

St. Mary's County sheriff's spokeswoman Cpl. Julie Yingling says there are injuries Tuesday at Great Mills High School but she didn't know how many or the severity of the injuries. She also said she had no information about fatalities.

Agents from the federal Bureau of Alcohol, Tobacco, Firearms and Explosives were headed to the scene.

The county sheriff said deputies are on the scene and that parents or guardians should stay away, going instead to Leonardtown High School to reunite with Great Mills students there.

Maryland Gov. Larry Hogan and Rep. Steny Hoyer tweeted that they're monitoring reports and urged people to follow the instructions of local law enforcement at the scene.

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9:10 a.m.

School officials report that there's been a shooting at a Maryland high school, that the 'event is contained' and the campus is on lockdown.

Federal agents from the bureau of Alcohol, Tobacco and Firearms are going to the scene, their agency tweeted.

The St. Mary's County Public Schools said on its website early Tuesday that there was a shooting at Great Mills High School, located in the southern end of the state.

The county sheriff said deputies are on the scene, and that parents or guardians should stay away, going instead to Leonardtown High School to reunite with Great Mills students there.

Maryland Gov. Larry Hogan and Rep. Steny Hoyer tweeted that they're monitoring reports and urged people to follow the instructions of local law enforcement at the scene.

ORIGINAL:

A shooting investigation is underway at a high school in St. Mary's County, Maryland, the sheriff's office confirms.

NBC Washington reports the shooting happened Tuesday morning at Great Mills High School in Great Mills, Maryland.

Multiple injuries have been reported.

A Twitter post from the St. Mary's County Sheriff's Office asked parents not to report to the school due to the incident, but to go to a high school in nearby Leonardtown instead.

Great Mills is about 60 miles southeast of Washington, D.C.

We will continue to follow this developing story.