BOSTON (Reuters) - Federal authorities have charged a California man with threatening to kill Boston Globe employees for the newspaper’s role leading this month’s defense of press freedoms by hundreds of U.S. news organizations against attacks by President Donald Trump.

FILE PHOTO: A customer walks past the front page of the Boston Globe newspaper referencing their editorial defense of press freedom and a rebuke of President Donald Trump for denouncing some media organizations as enemies of the American people, part of a nationwide editorial effort coordinated by the Boston Globe, at a newsstand in Cambridge, Massachusetts, U.S., August 16, 2018. REUTERS/Brian Snyder/File Photo

Prosecutors said Robert Chain, 68, called journalists “the enemy of the people” in threatening phone calls that echoed the phrase Trump has used to criticize unflattering news coverage through his campaign and years in office.

“In a time of increasing political polarization, and amid the increasing incidence of mass shootings, members of the public must police their own political rhetoric. Or we will,” Andrew Lelling, the U.S. attorney for Massachusetts and a Trump appointee, said in a statement on the arrest.

Prosecutors said Chain, who lives in Encino, California, was arrested on Thursday charged with one count of making threatening communications to interstate commerce. If convicted, he could face up to five years in prison.

Prosecutors said Chain made 14 threatening calls to the Globe from Aug. 10 through Aug. 22, including on Aug. 16 - the day the press freedom editorials ran - when he threatened to shoot employees in the head at 4 p.m. That prompted authorities to station police outside the paper’s Boston building.

“While it was unsettling for many of our staffers to be threatened in such a way, nobody – really, nobody – let it get in the way of the important work of this institution,” Jane Bowman, a Globe spokeswoman, said in a statement.

It was not immediately clear whether Chain had hired an attorney.

The Globe on Aug. 10 announced its plan for coordinated editorials defending press freedoms enshrined in the First Amendment of the U.S. Constitution. Newspapers and other media outlets across the United States joined in on Aug. 16.

The editorials led Trump to lash out on Twitter, saying, “THE FAKE NEWS MEDIA IS THE OPPOSITION PARTY. It is very bad for our Great Country....BUT WE ARE WINNING!” He did not provide specifics.

Trump continued bashing news media organizations on Wednesday and Thursday, lashing out at NBC and CNN, and again using the phrase “enemy of the people.”

In June, five people were shot dead at a newspaper in Annapolis, Maryland, allegedly by a man by a longstanding grudge against the paper, prosecutors said.