President Donald Trump ramped up his feud against the major news outlets in recent days with jabs on Twitter against MSNBC, CNN, the New York Times, and the Washington Post.

Trump has a history of commenting on the media, but has been more vocal since he launched his candidacy for president in 2015. Here's what you should know about some of his key conflicts.

Pre-political career

Trump has been in a long-running spat with "Vanity Fair" editor-in-chief Graydon Carter regarding the size of his hands. Carter wrote in November 2015 that he started calling Trump a “short-fingered vulgarian” in Spy magazine, which ran in the 1980s.

"To this day, I receive the occasional envelope from Trump," Carter wrote, claiming that Trump sends marked-up photos of himself, with "his hand in gold Sharpie in a valiant effort to highlight the length of his fingers."

In 2006, Trump sued journalist Timothy O'Brien for $5 billion in a libel case, after O'Brien's 2005 book "TrumpNation: The Art of Being The Donald," said the real estate mogul was worth $150 million to $250 million, the New York Times reported. The lawsuit was dismissed in 2009. An appeals court upheld the decision in 2011, according to Variety.

MSNBC

Trump has had an up-and-down relationship with "Morning Joe" hosts Joe Scarborough and Mika Brzezinski, critics of the president who once shared a friendly relationship with him during his candidacy.

Last week, Trump posted a series of tweets about the morning television show hosts, who are engaged to each another, including the claim that Brzezinski had a facelift. Trump's remarks were criticized by politicians on both sides of the aisle.



"I don't think it's a surprise to anybody that he fights fire with fire," White House Deputy Press Secretary Sarah Huckabee Sanders told Fox News.

Scarborough and Brzezinski later responded to Trump’s attack during their “Morning Joe” broadcast and with a joint op-ed published in the Washington Post called "Donald Trump is not well."

“President Trump launched personal attacks against us Thursday, but our concerns about his unmoored behavior go far beyond the personal. America’s leaders and allies are asking themselves yet again whether this man is fit to be president. We have our doubts, but we are both certain that the man is not mentally equipped to continue watching our show, 'Morning Joe,'" part of the op-ed read.

The feud between Scarborough and Trump continued on Twitter amid allegations in the op-ed that Scarborough and Brzezinski were told there would be a negative story about them in the National Enquirer "unless we begged the president to have the story spiked."

CNN

On Sunday, Trump tweeted a mock video that showed him pummeling a man in a business suit -- his face obscured by the CNN logo -- outside a wrestling ring. The brief clip seems to be a doctored version of Trump's 2007 appearance on World Wrestling Entertainment Inc.

A White House aide insisted the tweet should not send a chill across the media landscape.

"I think that no one would perceive that as a threat," homeland security adviser Tom Bossert 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."

CNN accused Trump of engaging in "juvenile behavior far below the dignity of his office." The tweet came a few days after CNN retracted a story about an investigation into a meeting between Trump supporter Anthony Scaramucci and Russian Direct Investment Fund CEO Kirill Dmitriev. Three CNN journalists subsequently resigned.

Earlier this year, Trump declined to allow CNN reporter Jim Acosta an opportunity to ask a question at a January press conference, after Trump spoke against BuzzFeed and CNN, which had reported on unverified documents which alleged Russia had compromising information about Trump.

Acosta repeatedly asked for a question from Trump, saying that the president-elect was "attacking" CNN.

"Not you, your organization is terrible," Trump said. Acosta, however, continued to request a chance to ask a question.

"Don't be rude," Trump later responded. "No, I'm not going to give you a question. I'm not going to give you a question. You are fake news."

Fox News

Trump got into a heated exchanged with moderator Megyn Kelly during a debate for Republican presidential candidates in August 2015.

"You've called women you don't like 'fat pigs, dogs, slobs, and disgusting animals,'" Kelly said.

"Only Rosie O'Donnell," Trump said, referring to the comedian and former host of "The View" with whom he has been in a years-long feud.

"For the record, it was well beyond Rosie O'Donnell," Kelly said during the exchange.

Kelly also spoke about inappropriate remarks Trump made about women on Twitter. She also recalled a "Celebrity Apprentice" moment when he told a woman that it would be nice to see her on her knees, asking, "Does that sound to you like the temperament of a man we should elect as president?"

Trump later remarked to CNN about Kelly, "She gets out and she starts asking me all sorts of ridiculous questions. You could see there was blood coming out of her eyes, blood coming out of her wherever."

Trump would tweet that his comment had been a reference to Kelly's nose. He later skipped a Fox News/Google debate in Des Moines, Iowa, in January 2016.

Trump, however, eventually sat down for an interview for "Megyn Kelly Presents." Kelly asked him about his re-tweet labeling Kelly a "bimbo."

"Did I say that?" he asked. Kelly said he did on multiple occasions.

"Oh, okay," Trump responded. "Excuse me."

The New York Times

Trump attacked the newspaper on Twitter last week, calling it a "fake news joke!" in reference to an article it had published about the Senate GOP health care bill titled "On Senate Health Bill, Trump Falters in the Closer's Role."

"Call your office, sir. @nytimes spoke to many, many, many members of your staff yesterday - & ran everything by your team," New York Times reporter Glenn Thrush tweeted.

Trump has called the newspaper "failing" on Twitter numerous times, including during his candidacy.

After he was elected president, Trump went to the New York Times building, where he participated in an hour-long interview with the newspaper as part of their up-and-down relationship.

The Washington Post

Trump also recently slammed the Washington Post in a June 28 post, calling it "#AmazonWashingtonPost."

In December 2015, Trump tweeted a claim that Amazon CEO Jeff Bezos owns the newspaper "for purposes of keeping taxes down at his no-profit company, @amazon."

Amazon lists the states where it collects sales taxes online.

Though Trump has previously attacked the Post, he has also had kinder words for the paper, Fortune noted. He tweeted a link to a Washington Post story in June 2016, saying, "Finally an accurate story from the Washington Post!"

The Associated Press contributed to this report.