News organizations have long been wary of angry reactions from their readers and viewers. But in the wake of Thursday’s killings at an Annapolis newspaper, they’re now on high alert, with some beefing up security around their newsrooms.

The fatal shooting of five employees of the Capital Gazette seems to have deepened a general sense among journalists that the ugly emails and phone calls they ordinarily receive might be something more than just a disgruntled individual blowing off steam.

“I can tell you that we’ve had a lot of discussions about security that we didn’t have before,” said Chad Lawhorn, editor of the Lawrence (Kan.) Journal-World. “This was a very painful reminder of the world we’re living in now.”

The most visible sign of heightened concern was the presence of New York City police officers stationed outside the headquarters of the New York Times in Manhattan in the wake of the news from Annapolis. In Washington, District police assigned a unit to guard the front of The Washington Post’s offices.

Journalists generally say the number of threats they receive has increased in recent years. While news organizations are loath to attribute this to a single factor, they say President Trump’s rhetoric demonizing the press hasn’t been helpful. (Trump on Friday backed off his usual media critique, saying at a White House event that the shootings “shocked the conscience of our nation and filled our hearts with grief. Journalists . . . should be free from the fear of being violently attacked while doing their jobs.”)

To be sure, the killing of journalists in the United States is exceptionally rare. The Committee to Protect Journalists lists seven such deaths since 1992, not counting the death of four reporters and editors at the Capital Gazette on Thursday. One of those killed, freelance photographer Bill Biggart, died in New York during the terrorist attacks on Sept. 11, 2001. Two others — Roanoke reporter Alison Parker and photojournalist Adam Ward — were fatally shot on camera while on a routine assignment in 2015.

But after Thursday’s killings, the United States is now the third-deadliest country for journalists in 2018, behind only Afghanistan and Syria, and harassment and threats are a constant shadow for reporters, with female journalists bearing a disproportionate share of the abuse.

On a few occasions, the threats have become flesh. A reader who apparently was set off by columnist Steven Petrow’s articles in USA Today sent the writer dozens of threatening Facebook messages last fall and earlier this year. Last week, the man turned up at Petrow’s home “in a rage,” he said, and pounded on his glass front door so hard that Petrow thought he was going to break it. Petrow called police; he later got a temporary protective order. He’s also bought Mace.

Audrey Cooper, editor of the San Francisco Chronicle, described the environment for news organizations on Twitter this way: “Every newsroom I know of, regardless of size or geographical area, has at least a handful of people who regularly harass its journalists. Every one.”

A New York Times spokeswoman, Eileen Murphy, thanked the NYPD for its response on Thursday and said the newspaper has expanded its own security measures “against the backdrop of increased threats and verbal attacks.” She declined to be specific, citing security concerns.

The Post was also vague about its precautions. But Gregg Fernandes, the executive in charge of the newspaper’s security, said the volume of “concerning threats” has risen over the past couple of years. “Anytime there is an event like this, we review our protocols and coordinate with local authorities,” he said.

Smaller news organizations such as the Capital Gazette seem especially vulnerable to people who might wish to do them harm. Many community papers are set up to encourage public interaction, with street-front offices located in prominent locations.

At the Montana Standard, a 10,000-circulation daily in Butte, for example, readers and would-be advertisers stroll straight into a first-floor office. “It’s pretty open,” says David McCumber, the paper’s editor. “We certainly have some security, but the fact is, we have to interact with the public.”

McCumber, who has edited newspapers in San Francisco, Seattle, Tucson, El Paso and Washington, among others, over his decades-long career, thinks reporters have always been vulnerable because they deal with issues that spark emotional reactions. But Annapolis, he said, has exposed some deeper, uglier fault lines.

“I think we’ve all have dealt with people who seemed irrationally angry about something. That goes with the territory,” he said. “But we’ve seen the level of animus toward journalists hike up in recent times. . . . With access to firearms being universal, and with the polarization and incivility we’re seeing, it’s a dangerous mix. I hope we haven’t crossed some line.”