'Multiple deaths' in Maryland shooting
The shooting happened on Thursday morning in the Perryman area, Harford County, about 40km (25 miles) north-east of Baltimore.
A number of people were injured. A suspect is now in custody.
The Harford County Sheriff's Office described the situation as "fluid", urging residents to avoid the area.
WATCH LIVE: 3 killed in Maryland 'active shooter' situation
ABERDEEN, Maryland -- Three people were killed Thursday morning in a shooting at a Rite Aid distribution center in northeast Maryland, officials said.
A law enforcement official with knowledge of the shooting stressed that the number of dead is based on preliminary information. The official wasn't authorized to discuss details by name and spoke on condition of anonymity to The Associated Press.
The attack came nearly three months after a man armed with a shotgun attacked a newspaper office in Annapolis, Maryland, killing five staff members.