CNN has severed ties with pro-Trump contributor Jeffrey Lord after he used a Nazi reference in a tweet directed at the president of the liberal media watchdog group Media Matters.

"Nazi salutes are indefensible," CNN said in a statement. "Jeffrey Lord is no longer with the network."

Lord tweeted the Nazi phrase to Angelo Carusone on Thursday morning after a back-and-forth on Twitter that followed a column Lord wrote for the American Spectator that called both Carusone and his website "Media Matters Fascists." Lord was upset at the organization's campaign for Fox News to fire host Sean Hannity.

Lord shared the article on Twitter and directed it at Carusone, who responded, "Your headline has a mistake in it. Why do you expect anyone to take you seriously when you don't take yourself seriously."

Lord's response was "Sieg Heil!"

Lord, who served in the White House as an associate political director under President Ronald Reagan and now lives outside Harrisburg, spoke with CNN's Brian Stelter after his firing Thursday.

"I love CNN," said Lord, one of Trump's most vocal defenders on the network. "I feel like they are caving to bullies here."

On Twitter, Lord posted a one-word response following his ouster:

During his two-year tenure as a contributor, Lord often made controversial statements as a panelist on CNN shows. He once referred to the Ku Klux Klan as the "military arm of the Democratic Party" and described Trump as "the Martin Luther King Jr. of health care."

Lord joined CNN about two years ago, and quickly became part of a contingent of 12 contributors who would defend Trump on the network. Lord was among the names CNN chief executive Jeffrey Zucker touted to the New York Times this year, referring to the pro-Trump panelists as "characters in a drama" intended on hitting a viral nerve that could be debated and shared throughout the day.

"Everybody says, 'Oh, I can't believe you have Jeffrey Lord or Kayleigh McEnany' — but you know what?" Zucker told the Times. "They know who Jeffrey Lord and Kayleigh McEnany are."

Over the weekend, McEnany announced she had left CNN and hosted a segment called the "real news" on Trump's official Facebook account. On Monday, the Republican National Committee named McEnany the party's new spokeswoman.

In an interview this summer with my colleague Aubrey Whelan, Lord opened up about the difficulties of juggling appearances on the network while trying to take care of his 97-year-old mother in their Camp Hill home.

"I'll do it probably until I can't," Lord said. "I mean, life moves on, but I love to write, and this was why I wanted to become a writer: to do this, and do other things in the media if possible. You're on TV and then you're not. The main thing is to stay focused. And I could not possibly have predicted this in my wildest imagination."

Lord is the third CNN contributor with whom the network recently severed ties. In May, it cut ties with comedian Kathy Griffin after she shared a provocative photo of herself holding a bloody, severed head meant to resemble Trump. Griffin had co-anchored the network's New Year's Eve coverage alongside Anderson Cooper since 2007.

CNN cut ties in June with Reza Aslan and canceled his documentary series after the vocal Trump critic blasted the president for his response to a June terror attack on London Bridge that killed eight people.