WASHINGTON - Several people were feared killed Thursday in a shooting at the building that houses the Capital Gazette, a daily newspaper published in Annapolis, a historic city an hour east of Washington.

A reporter for the Capital Gazette, Phil Davis, tweeted that a “gunman shot through the glassdoor to the office and opened fire on multiple employees.” He said several people were killed.

“There is nothing more terrifying than hearing multiple people get shot while you’re under your desk and then hear the gunman reload,” Davis said.

Up to four people had been killed, according to CBS News quoting two sources.

The newspaper is located in a four-storey office building in Annapolis, the capital of the US state of Maryland.

The White House said President Donald Trump had been briefed.

“ATF Baltimore is responding to a shooting incident at the Capital Gazette in Annapolis,” the Bureau of Alcohol, Firearms, and Tobacco said on Twitter.

The local Anne Arundel police force added: “Confirming active shooter at 888 Bestgate Road in Annapolis. Building evacuated. Officers continuing to search building.”

“Absolutely devastated to learn of this tragedy in Annapolis,” Maryland Governor Larry Hogan said. “Please, heed all warnings and stay away from the area. Praying for those at the scene and for our community.”

On TV reports, people could be seen leaving the building with their hands up, as police officers urged them to depart through a parking lot and officers converged on the building.

A gas station employee near the shooting site described a flood of police activity in the area as he sat tight inside his still-open workplace.

In a phone interview, Carlos Wallace, who works at a station just down the street from the newspaper’s offices, estimated that “dozens of dozens” of law enforcement vehicles and ambulances had raced toward the scene with sirens blaring.

“The road is blocked off real good. It’s like dozens of dozens of emergency vehicles, police cars of all types, explosive vehicles, battering ram vehicles, all kinds of stuff,” Wallace said at about 3:50 pm Thursday.