After a Mother Jones report on Thursday asserted that Bill O'Reilly had made false claims about his coverage of the Falklands War in 1982, the Fox News host responded furiously.

In interviews, O'Reilly said the story was a "giant piece of defamation," "a lie," and a smear. He called one of the writers, David Corn, a "disgusting piece of garbage," a "guttersnipe liar," and a "far-left assassin."

Corn, the Washington bureau chief for Mother Jones, told CNNMoney that O'Reilly was resorting to ad-hominem attacks to distract from the substance of his report, which he co-authored with Daniel Schulman.

"There's an undeniable contradiction" in what O'Reilly has said about his Falklands coverage, Corn said, urging reporters to focus on that part of the story.

The back-and-forth comes two weeks after "NBC Nightly News" anchor Brian Williams apologized for misstating his experience on an Iraq War mission in 2003. Williams was later suspended amid further scrutiny of his claims; a fact-checking investigation is ongoing.

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Fox orchestrated a full-throated response right away on Thursday; O'Reilly told TVNewser that he had "talked to about eight or nine reporters."

When asked for comment, a Fox News spokeswoman deferred to O'Reilly's other interviews.

Corn and Schulman's report detailed several times when O'Reilly said that he had spent time in a "war zone" while covering the Falklands conflict as a reporter for CBS News.

The problem, as CBS News's chief Washington correspondent Bob Schieffer explained to Mother Jones, is that the only "war zone" was in and around the islands, and "nobody from CBS got to the Falklands."

Schieffer, who was the network's lead correspondent covering the conflict at the time, said he "came close" to reaching the Falklands, but the task proved "impossible." He, O'Reilly and other reporters were based in Buenos Aires, Argentina.

Corn said Mother Jones started to piece together the report last week. It began to ask Fox News for comment on Thursday morning, and never heard back from O'Reilly or any of the network's representatives.

Shortly after its report was published on Thursday afternoon, however, O'Reilly condemned it in a series of interviews with other outlets. He insisted that everything he said about his coverage of the conflict was true.

"I was not on the Falkland Islands and I never said I was," O'Reilly told Politico. "I was in Buenos Aires."

The Mother Jones report highlighted an example from 2013, when O'Reilly recalled that he had been "in a war zone in Argentina, in the Falklands."

In another interview, this one with Mediaite, O'Reilly said his descriptions referred broadly to the story he was assigned to cover.

"If you were assigned to a war, you put on your resume you covered the Falklands, the Middle East, El Salvador, wherever it is where you were sent," he said. "This is what journalists do."

O'Reilly said he bore witness to a chaotic scene in Buenos Aires after the war -- something he called a "combat situation."

Corn told CNNMoney this was akin to "saying that if you're in D.C. covering a protest during the Vietnam War, you were in Vietnam."

Corn is a regular on cable news; he was a paid contributor to Fox News until 2008. He now has a similar position at Fox's rival MSNBC. He is perhaps best known for breaking the news about Mitt Romney's "47 percent" remarks.

O'Reilly asserted that Corn has been out to get Fox News for years. He said to TVNewser that he thought once reporters "verify what I'm saying, because it's easily verifiable, then I expect David Corn to be in the kill zone."

Corn said he thought the "kill zone" comment was intended to be threatening.

--Brian Stelter contributed reporting.