Police in the US state of Maryland responded to reports of a gunman and said there were at least two victims, while the US Navy reported an “active shooter incident” at Fort Detrick involving sailors.

Police said the suspect was dead and two victims were in critical condition.

According to police, a shooting happened at an address where a concrete business is located and about four miles from Fort Detrick.

The Navy did not release further details.

Jeremy Mutschler, director of marketing for Nicolock Paving Stones, said that his understanding is that the shooting was near the company’s Frederick location but not at the business itself.

“One of the victims who was wounded entered our facility looking for help and we were able to assist and call the authorities,” said Mr Mutschler, who is based in New York.

Citing police, The Baltimore Sun reported that both of the victims sustained life-threatening injuries in the shooting and were flown to the University of Maryland Shock Trauma Centre in Baltimore.