Nearly 350 news organizations are set to publish editorials on Thursday pushing back against Donald Trump’s attacks on the media and defending freedom of the press.

The publications are participating in a push organized by the Boston Globe to run coordinated editorials denouncing what the paper called a “dirty war against the free press”.

As of Wednesday morning, 343 publications had pledged to participate, said Marjorie Pritchard, the Globe’s deputy managing editor overseeing the opinion page.

The Guardian has also joined the effort and has published an editorial alongside outlets around the United States.

“Donald Trump is not the first US president to attack the press or to feel unfairly treated by it. But he is the first who appears to have a calculated and consistent policy of undermining, delegitimising and even endangering the press’s work,” the Guardian’s editorial says.

Trump has routinely attacked the press as a whole as well as individual reporters, labeling factually accurate reports “fake news” and calling the news media “the enemy of the people”.

A majority of Republicans (51%) now regards the media as the enemy of the American people pic.twitter.com/hgWaTOxAf8 — Aaron Blake (@AaronBlake) August 14, 2018

The Globe’s opinion page put out the call for a mass response last week.

“We propose to publish an editorial on August 16 on the dangers of the administration’s assault on the press and ask others to commit to publishing their own editorials on the same date,” the pitch to editors said.

The hundreds of newspapers and sites participating include the New York Times, Chicago Sun Times, Philadelphia Inquirer and Miami Herald. A host of smaller papers from cities and towns around the country are also joining in.

Trump has stepped up his attacks on the media in recent weeks. At a rally in Pennsylvania, he pointed out the journalists covering the event and derided them as “fake, fake, disgusting news”. The White House barred a CNN reporter from covering a public event after she asked Trump a question.

The outgoing UN human rights commissioner, Zeid Ra’ad al-Hussein, told the Guardian this week that Trump’s comments are “very close to incitement to violence”.

The rhetoric “could quite easily lead to harm being inflicted on journalists just going about their work and potentially some self-censorship,” he said.

Each newspaper participating in the effort will write its own separate editorial, and organizers say they expect the pieces to reflect different political views but a uniform alarm at the recent attacks.

“It is not the press’s job to save the United States from Mr Trump. It is the press’s job to report, delve, analyse and scrutinise as best it can and without fear,” the Guardian’s editorial says.

“Mr Trump’s insults and incitements are a calculated danger to that, and to the respect, civility and dialogue that should exist between the press and its readers. The Guardian stands with the US press in its efforts to maintain the objectivity and the moral boundaries that this president – like so many others in much more dangerous parts of the world – is doing so much to destroy.”