Three people have been killed in a shooting in the US state of Maryland in what authorities describe as an “active shooter” situation.

The official stressed that the number of three deaths is based on preliminary information.

The Harford County Sheriff’s Office tweeted that there was a shooting on Thursday morning in the Perryman area that involves “multiple victims”.

Maryland Shooting
Authorities respond to the shooting (Jerry Jackson/AP)

They warned that the situation was still fluid and asked people to avoid the area.

The FBI’s Baltimore field office tweeted that it was responding and assisting the sheriff’s office with the situation.

The Baltimore field division of the federal Bureau of Alcohol, Tobacco, Firearms and Explosives tweeted that its special agents were responding too.