ANNAPOLIS (REUTERS, AFP, NYTIMES, WASHINGTON POST) - A man brandishing a shotgun and carrying smoke grenades walked into the office of a small newspaper in Maryland on Thursday (June 28) and killed at least five people in a targeted assault, one of the deadliest attacks recorded on a US media outlet, authorities said.

The suspect has been identified as Jarrod Ramos, 38, who had a long-running feud with the paper, sources told The Baltimore Sun.

"This was a targeted attack on the Capital Gazette," said Acting Chief William Krampf of the Anne Arundel County Police Department. "This person was prepared to shoot people. His intent was to cause harm."

The chilling attack on the Capital Gazette was covered in real time by some of the journalists who found themselves under siege. A summer intern, Mr Anthony Messenger, tweeted out the address of the office building where the newsroom is based, saying, "please help us."

A reporter for the newspaper described the scene in the newsroom as being "like a war zone," with reporters hiding under their desks for safety.

Mr Phil Davis, who identified himself as a courts and crime reporter at the Capital Gazette, which runs multiple newspapers in its Annapolis office, tweeted that multiple people had been shot. Mr Davis said in an interview with the Baltimore Sun, which owns the Gazette, that he and others were still hiding under their desks when the shooter stopped firing.

"I don't know why. I don't know why he stopped," he said. "But as much as I'm going to try to articulate how traumatising it is to be hiding under your desk, you don't know until you're there and you feel helpless."

Mr Davis described how the gunman "shot through the glass door to the office" before opening fire.

The gunman was silent as he stalked the newsroom, stopping once to reload as journalists huddled in fear under their desks, Mr Davis said in a telephone interview.

Once the police arrived, staff members put their hands in the air and shouted, "We're not him," Davis recalled.

The gunman was hiding under a desk as the police moved in. He did not exchange gunfire with officers when he was taken in.

The suspect appeared to have damaged his fingertips to try to avoid detection and was refusing to cooperate with law enforcement, Baltimore TV station WJZ and other local media reported.

"He didn't have enough bullets for us," Mr Davis said, struggling to grapple with the images of his fallen colleagues. "It was terrifying to know he didn't have enough bullets to kill everyone in that office, and had to get more."

Shortly before 6pm, at least three helicopters were still circling, and lines of silent police cars, with lights flashing, blocked off the main roads leading up to the newsroom at 888 Bestgate Road.

Yellow police tape flapped in the wind, keeping people and journalists away from the area.

"I was so scared," said Ms Rayne Foster, who works on the fourth floor of the building. "I was very scared."

Locked in a room with about a dozen others, Ms Foster had sent a text to her daughter: "There's an active shooter. I love you."

"I was taking deep breaths," she said. "We could hear them busting out the glass doors and windows. It was so surreal."

Ms Karen Burd, 27, was on her fourth day at work in a tax litigation firm in the building when a co-worker told her there was a shooter.

Her first thought was to find a room in which they could barricade themselves. She and four others crammed into the room and called 911.

Soon, police were banging on the door.

"I started praying," she said, tears filling her eyes. "You just think, 'Is this going to be my last day?'"

The police bomb squad investigated a knapsack that was found near the suspected shooter and contained an unknown device.

Among those killed was the veteran columnist, editor and journalism teacher Rob Hiaasen.

Mr Hiaasen, 59, the brother of best-selling author and journalist Carl Hiaasen, had been a feature writer at the Baltimore Sun for 15 years before moving to the Capital in 2010 as an assistant editor.

Wendy Winters, 65, Rebecca Smith, 34, Gerald Fischman, 61, and John McNamara were also killed, he said. Ms Smith was a sales assistant and the others were journalists.

In 2012, Ramos filed a defamation lawsuit against the paper and a columnist over a July 2011 story that covered a criminal harassment case against him.

Mr Thomas Hartley, a former columnist for The Capital, one of the group's papers, wrote a column describing the suspect's interactions with an unnamed woman Ramos contacted over Facebook, court documents showed. Mr Hartley said Ramos sent her numerous e-mails in which he called her vulgar names and told her to kill herself.

He brought the suit against the columnist, Eric Hartley, naming Capital Gazette Communications and Mr Thomas Marquardt, the paper's former editor and publisher, as defendants.

Ramos had pled guilty to criminal harassment five days before Mr Hartley published his column, records showed. He claimed in court documents that his perspective was not fairly represented. His lawsuit was dismissed in 2013, and an appellate court upheld the dismissal in 2015.

As the case made its way through the courts, a Twitter user calling himself Jarrod W. Ramos posted numerous tweets critical of the Capital Gazette, Mr Hartley and the Maryland judges.

"Yes, Eric Thomas Hartley, you moved to... oh just go ahead and kill yourself already before I do (legally in court)," the user tweeted in 2014.

The account went silent from January 2016 until Thursday, just before the shooting at the Capital Gazette.

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. Davis later said he was safe and being interviewed by police.

The daily newspaper and sister publications have an editorial staff of around 45 supported by a sales and advertising team of about 10 staff, according to the company's website. Police said they were on the scene in about a minute from the initial call about the shooting.

President Donald Trump has been briefed on the shooting, White House spokeswoman Lindsay Walters said. "My thoughts and prayers are with the victims and their families. Thank you to all of the First Responders who are currently on the scene," Trump said in a tweet.

His press secretary on Thursday described the killing of five people at a newsroom in Annapolis as an attack on "innocent journalists".

"Strongly condemn the evil act of senseless violence in Annapolis, MD," tweeted Sarah Sanders. "A violent attack on innocent journalists doing their job is an attack on every American. Our prayers are with the victims and their friends and families."

Police 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 organisations as a precaution.

The New York Police Department said its decision was not based on any specific threat, "but rather out of an abundance of caution until we learn more about the suspect and motives behind the Maryland shooting."

The department described such deployments as "a standard practice to shift resources strategically during active shooter or terrorist events".

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. About 170 people were evacuated.

A 2015 court document quoted Ramos' lawyer as saying that Ramos had worked for the US Bureau of Labour Statistics for six years.

Past and present employees of the newspaper chain were struggling to understand what could have prompted such an attack.

"The Capital, like all newspapers, angered people every day in its pursuit of the news," Mr Tom Marquardt, a former executive editor and publisher at The Capital, wrote on Facebook.

"In my day, people protested by writing letters to the editor; today it's through the barrel of a gun. Sure, I had death threats and the paper had bomb threats. But we shrugged them off as part of the business we were in."

Mr Jimmy DeButts, an editor at the Capital Gazette, tweeted that he was devastated, heartbroken and numb.

"I'm in no position to speak, just know @capgaznews reporters & editors give all they have every day. There are no 40 hour weeks, no big paydays - just a passion for telling stories from our community," he wrote.

Even as the authorities continued to pore over the newsroom for clues, the Capital Gazette announced on Thursday that it would be publishing an edition on Friday.

"I can tell you this: We are putting out a damn paper tomorrow," reporter Chase Cook wrote on Twitter.