The Frederick Police Department said on Twitter: “There are currently two victims and one suspect is whereabouts.”
According to the police, the shooting took place in the northeast of the city, about 4 miles east of the US Army’s Fort Delhi.
The ATF office in Baltimore said on Twitter that agents of the Alcohol, Tobacco, Firearms and Explosives Administration are responding to assist.
Frederick is about 50 miles northwest of Washington, DC.
This developing story will be updated.