US President Donald Trump has ramped up his attacks on mainstream media, tweeting a mock video of himself tackling and repeatedly striking a man with a CNN logo in place of his head.

The video appeared to be a modified version of a 2007 appearance by Trump at World Wrestling Entertainment's WrestleMania 23 promotion, in which Trump "takes down" WWE Chairman Vince McMahon.

In Sunday's tweet, after Trump appears to beat on the CNN effigy, a logo reading "FNN Fraud News Network" appears at the bottom of the screen in a script similar to that of CNN.

Trump has repeatedly made known his disdain for some media, calling it "the enemy of the American people" and frequently referring to mainstream news organisations as "failing" or "fake news." He has been particularly scathing of CNN.

The video takes his criticism to a new level and drew criticism from news organisations and many social media users, with some accusing Trump of inciting violence against journalists.

"It is a sad day when the President of the United States encourages violence against reporters," CNN said in a statement later on Sunday.

"Instead of preparing for his overseas trip, his first meeting with Vladimir Putin, dealing with North Korea and working on his health care bill, he is instead involved in juvenile behavior far below the dignity of his office," the network added.

Bruce Brown, the executive director of the Reporters Committee for Freedom of the Press, condemned the video as a "threat of physical violence against journalists". He said Trump's tweet was "beneath the office of the presidency".

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A White House aide, however, defended the tweet.

"I think that no one would perceive that as a threat," Tom Bossert, a homeland security adviser, said. "I hope they don't. But I do think that he's beaten up in a way on cable platforms that he has a right to respond to."

First, Trump tweets that the free press is the “enemy of the American people”



Now, he tweets a video of him assaulting “CNN”



1st A is dead — William LeGate (@williamlegate) July 2, 2017

Leonard Steinhorn, a professor of public communication at the American University in Washington, said Trump's tweet was aimed at his supporters as part of his "permanent campaign" to get re-elected in 2020.

"His base loves that," he told Al Jazeera. "That is red meat on a July 4 barbecue for them, this is exactly what they want to hear," Steinhorn added.

"Trump's whole approach on all of this is you rouse the base, you keep the 40 percent loyal to you, and then when 2020 comes around you've got them rock solid on your side - all you need to do is to pry away enough voters by criticising your opponents, the way he is masterful at doing, to be able to get re-elected."

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Steinhorn also said that the media should take some of the blame for building Trump up during the election in order to score high ratings.

"The media certainly have responsibility when they were covering his antics and his entertainment value versus the content of what he was saying and applying some critical reporting to that," he said, noting that news organisations have been "much better" in covering Trump since he became president.

"But during the campaign, when you had an empty podium, and CNN was focused on an empty podium waiting for Trump for some sort of big splash which turned out to be nothing ... then the media certainly has to take some responsibility on that," added Steinhorn.

This was a sentiment echoed by many on social media.

Really having trouble with the rewriting of history where CNN is a worthy white knight victim of Trump. It milked him for ratings not truth. — Nesrine Malik (@NesrineMalik) July 2, 2017

Al Jazeera's Kimberly Halkett, reporting from Washington, DC, said that the president did not seem to have any intention to change his rhetoric despite the growing criticism towards him, including some voices from his own Republican Party.

"When speaking in Washington on Saturday evening, Trump said that the fake media is trying to silence him. He said he will not let them," Halkett said.

"The tweet certainly underscores the divide that remains in the US. It has no sign of letting up. And the latest message in the president's tweet is not unifying."

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Trump's Sunday tweet followed a crude and highly personal Twitter attack last week on MSNBC co-hosts Joe Scarborough and Mika Brzezinski - the president said Brzezinski had a "low I.Q." and said he had seen her bleeding after a facelift

That attack drew condemnation from Republicans, including Speaker of the House of Representatives Paul Ryan, and Democrats alike.

Amid a torrent of criticism over his attack on Brzezinski, Trump doubled down on Saturday, tweeting: "My use of social media is not Presidential - it's MODERN DAY PRESIDENTIAL. Make America Great Again!"