A senior federal law enforcement source told CBS News that at least five people were dead and several others gravely wounded in the incident happened on Thursday afternoon, presstv.com wrote.
The first reports of the shooting came at 2:40 p.m. at The Capital Gazette building in Annapolis, after the shooter entered the building, which also houses other businesses. The Gazette is a local newspaper owned by The Baltimore Sun.
Employees were evacuated by police from the building with hands raised above their heads. Police were searching through the building and called the situation "active and ongoing.”
A spokeswoman for the city said the suspect had been arrested.
No motive has been known yet but a law enforcement official said the shooting was not being treated as an incident of terrorism, rather as a local incident.
Phil Davis, a Gazette reporter, tweeted that he was in the building when the shooting took place. He wrote on Twitter that the gunman had "shot through the glass door to the office and opened fire on multiple employees".
"Can't say much more and don't want to declare anyone dead, but it's bad."
He said that the gunman had shot "multiple people at my office, some of whom are dead.”
"There is nothing more terrifying than hearing multiple people get shot while you're under your desk and then hear the gunman reload."
Anne Arundel County Executive Steve Schuh said during a news conference, "We've had a terrible shooting incident here this afternoon.”
Each year, more than 32,000 people die as a consequence of gun-related violence in the United States, which is by far the highest among industrialized countries, according to the Centers for Disease Control and Prevention.
Some experts say the NRA, one of the most influential lobbying groups in Washington, is largely responsible for the gun violence epidemic across the US.