Police near the scene of the shooting incident in Annapolis, Maryland, June 28, 2018. Photo: Reuters / Joshua Roberts.

A gunman fired through a glass door at a newspaper in the Maryland capital of Annapolis and sprayed the newsroom with gunfire on Thursday, killing at least five people and injuring several others, authorities said.

The suspect has been apprehended and no motive is known for the attack at the Capital Gazette newspaper, local political leaders said.

Law enforcement in Baltimore and New York City deployed protective forces to major media outlets as a precaution, authorities said.

“The shooter is in custody and is being interrogated at this time,” Anne Arundel County Executive Steve Schuh told a news conference.

Maryland Governor Larry Hogan said at the news conference: “It’s a tragic situation. We don’t have all the information yet, and we can’t give all the information yet, but we have had several fatalities.”

For now, the Annapolis shooting is being treated as a local incident and not one that involves terrorism, a law enforcement official said. The Federal Bureau of Investigation is on the scene assisting local authorities, the official said.

Phil Davis, who identified himself as a courts and crime reporter at the Capital Gazette, tweeted that multiple people had been shot.

Davis said a single shooter “shot multiple people at my office, some of whom are dead.” He later said he was safe and being interviewed by police.

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

President Donald Trump has been briefed on the shooting, White House spokeswoman Lindsay Walters said.

“Our thoughts and prayers are with all that are affected,” she said. Trump was aboard Air Force One, returning to Washington from an event in Wisconsin.

One law enforcement source told CBS News the suspect is a male in his 20s who had no identification on him. Two law enforcement sources told CBS News the suspect used a shotgun.

Police also went to the offices of the Baltimore Sun as a precaution, that paper reported.

The New York Police Department said it was beefing up security at New York-based news organizations as a precaution.

“We’re deploying units from our Critical Response Command to news outlets throughout New York City,” said Officer Andrew Lava, an NYPD spokesman.

“There is no active threat at this time,” he said.

Agents from the Baltimore office of the Bureau of Alcohol, Tobacco, Firearms and Explosives were responding to the incident, the bureau tweeted.

Police are checking the building in Annapolis for explosives and whether more than one suspect was involved, Anne Arundel County police spokesman, Lieutenant Ryan Frashure, told reporters.

Live video images showed people leaving the building, walking through a parking lot with their hands in the air. Scores of police vehicles were on the scene.