Great Mills High School in Great Mills, Maryland, was on lockdown after a shooting there this morning, St. Mary's County Public Schools said in a statement.
Several people were shot and injured but the number of victims is unclear, as is their condition, the St. Mary’s County Sheriff’s Department said.
The school district said "the event is contained."
Students are being evacuated from the school and bused to a reunification center at nearby Leonardtown High School, the school district said.
“The building is orderly and the sheriff’s office is conducting an investigation,” the district added.
Senior Terrence Rhames, 18, was standing outside his first class when he heard a gunshot and started running, The Baltimore Sun reported.
He said he saw another student fall out of the corner of his eye.
“I just thank God I’m safe,” Rhames told the newspaper. “I just want to know who did it and who got injured.”
Great Mills is located about 60 miles southeast of Washington, D.C.
Maryland Gov. Larry Hogan tweeted that he is closely monitoring the situation, adding that state police are “in touch with local law enforcement and ready to provide support.”
"Our prayers are with students, school personnel, and first responders," Hogan added.
FBI and ATF agents are responding.
Additional information was not immediately available.
This story is developing. Please check back for more updates.