ANNAPOLIS, Md. (AP) -- A man with a long grudge against Maryland's capital-city newspaper was ordered held in jail Friday on five counts of first-degree murder after police said he blasted his way into the newsroom with a pump-action shotgun, killing five people in one of the deadliest attacks on journalists in U.S. history.

Jarrod W. Ramos, 38, was swiftly arrested as he tried to hide under a desk Thursday afternoon at the Capital Gazette in Annapolis, police said.

"The fellow was there to kill as many people as he could kill," Anne Arundel County Chief Timothy Altomare said.

Ramos was "uncooperative" with his interrogators, police said, and in court papers, authorities described him as "recalcitrant."

Appearing by in court via video before he was denied bail, he appeared to watch attentively but never spoke. His public defenders had no immediate comment outside court.

President Donald Trump said the attack filled Americans' hearts with grief. "Journalists, like all Americans, should be free from the fear of being violently attacked while doing their jobs," he said.

Prosecutor Wes Adams said Ramos carefully planned the attack, barricading the back door so victims couldn't escape, and using "a tactical approach in hunting down and shooting the innocent people."

Ramos had a well-documented history of harassing the paper's journalists, a feud that apparently began over a column about Ramos pleading guilty to harassing a woman. He filed a defamation suit against the paper in 2012 that was thrown out as groundless, and he repeatedly railed against its staff members in profanity-laced tweets.

Police said surveillance video recorded the attack, which began with a shotgun blast that shattered the glass entrance to the open newsroom. Journalists crawled under desks and sought other hiding places, describing agonizing minutes of terror as they heard his footsteps and the repeated blasts of the weapon.

Officers swiftly responded and arrested him without firing a shot, police said. They recovered a gun and said he also carried smoke grenades. Some 300 local, state and federal officers converged on the scene, Altomare said.

The "bad guy" was identified quickly with help of facial recognition technology, Altomare said, refusing to give Ramos the satisfaction of using his name. The chief said the weapon was a 12-gauge pump-action shotgun, legally purchased about a year ago.

The rampage immediately stirred fears that the recent political attacks on the "fake news media" and the branding of reporters as "enemies of the people" had finally exploded into violence. But by all accounts, Ramos had a longstanding, specific grievance against the paper.

"Strongly condemn the evil act of senseless violence in Annapolis, MD," White House press secretary Sarah Sanders tweeted. "A violent attack on innocent journalists doing their job is an attack on every American."

Ramos so routinely sent profanity-laced tweets about the paper and its writers that retired publisher Tom Marquardt said he called police in 2013, telling his wife at the time, "This guy could really hurt us."

The chief said newspaper at the time didn't want to press charges for fear that would "exacerbate an already flammable situation."

In 2015, Ramos tweeted that he would like to see the paper stop publishing, but "it would be nicer" to see two of its journalists "cease breathing."

Investigators were reviewing his social media postings and searching his apartment in Laurel, Maryland, for clues to the violence.

"We had the instances in 2013, and then it went dark, and my understanding is that shortly before the incident, there were some posts," Altomare said.

Those killed included Rob Hiaasen, 59, the paper's assistant managing editor and brother of novelist Carl Hiaasen. Carl Hiaasen said he was "devastated and heartsick" at losing his brother, "one of the most gentle and funny people I've ever known."

Also slain were editorial page editor Gerald Fischman, special projects editor Wendi Winters, reporter John McNamara and sales assistant Rebecca Smith.

The newspaper said two other employees were treated for minor injuries.

Phil Davis, the courts and crime reporter, told his newspaper that the newsroom had become a "war zone."

"I'm a police reporter. I write about this stuff — not necessarily to this extent, but shootings and death — all the time," he said. "But as much as I'm going to try to articulate how traumatizing it is to be hiding under your desk, you don't know until you're there and you feel helpless."