Updated at 1 p.m. ET
Two students were injured when another student opened fire at Great Mills High School in St. Mary's County, Md., according to the local sheriff. The shooter was confirmed dead after being taken to a hospital.
"A male student produced a handgun and fired a round, wounding a female student and another male student in a hallway of Great Mills High School just before classes begun" around 8 a.m. Tuesday, St. Mary's County Sheriff Timothy Cameron told reporters at a news conference.
The two victims have been taken to local hospitals. The male student is in stable condition, and the female student is in critical condition, Cameron stated.
A school resource officer engaged the shooter after he started firing, Cameron told reporters. The resource officer "fired a round at the shooter, simultaneously the shooter fired a round as well," Cameron said. They are investigating whether the officer's rounds struck the shooter, and the sheriff added that the officer was not injured.
The identities of the victims and the shooter have not been released, nor is it clear what their relationship is to one another.
Witnesses to the shooting are being questioned at a secured area in the high school, the sheriff said. The school district said that the school was being evacuated and that the rest of the students were being taken to Leonardtown High School. Parents were being asked to go there rather than to Great Mills.
The FBI and the Bureau of Alcohol, Tobacco, Firearms and Explosives said their agents are on the scene assisting the sheriff's department.
Great Mills High School is located in southern Maryland, about 60 miles southeast of Washington, D.C.
"This is what we train for, this is what we prepare for, and this is what we pray we never have to do," said the sheriff. "And on this day we realize our worst nightmare, that our greatest asset — our children — were attacked in one of our places, a bastion of safety and security, one of our schools."
According to The Bay Net, a southern Maryland news site, authorities investigated potential threats to Great Mills High School last month after reports circulated on social media.
The news site said that the school principal said in a letter to parents that the school and law enforcement assessed the threat and said it "has not been validated at this time." At Tuesday's press conference, the sheriff said that they are now investigating whether anything on social media is linked to this attack.
The shooting comes just over a month after the shooting that killed 17 people at Marjory Stoneman Douglas High School in Parkland, Fla.
"That's what we're talking about right now across the country," Cameron added. "The notion of 'it can't happen here' is no longer a notion."
Last week, tens of thousands of students walked out of classrooms to call for firmer action against gun violence. Mass demonstrations are expected this weekend in Washington, D.C., in favor of stricter gun regulations, a protest organized by Parkland shooting survivors.
Emma Gonzalez, a Parkland student who has been outspoken in calling for tighter gun laws, tweeted a message of support for Great Mills students.
Maryland Gov. Larry Hogan said in a statement that he was praying for the Great Mills community. "But prayers are not enough," Hogan said. "Although our pain remains fresh and the facts remain unclear, today's horrible events should not be an excuse to pause our conversation about school safety.
"Instead, it must serve as a call to action."
This is a developing story. Some things that get reported by the media will later turn out to be wrong. We will focus on reports from police officials and other authorities, credible news outlets and reporters who are at the scene. We will update as the situation develops.