There are reports that several people were injured in a shooting at Great Mills High School in St. Mary’s County, Maryland, on Tuesday morning. Police say the school is on lockdown but the scene is “contained.”

The sheriff said three people, including the shooter, are in critical condition and have been transported to area hospitals. The school resource officer reportedly engaged the suspect quickly.

School officials are telling parents/guardians to go to Leonardtown High School for reunification with their GMHS students.

The shooting comes four days before the National March for Our Lives protests that will be held on March 25. It comes days after students at Great Mills High School participated in the National School Walkout last week to call for stricter gun laws.

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