US President Donald Trump has demanded that Fox News fire its national security correspondent after she confirmed claims that the Republican leader had disparaged the military -- a bombshell that has dogged him for two days. 

Trump came under fire after The Atlantic magazine reported that he had called Marines killed in action in World War I "losers" and "suckers" in connection with a November 2018 visit to France when he skipped a visit to a US military cemetery.

The official explanation for that missed visit was bad weather.

Fox News correspondent Jennifer Griffin said two former administration officials had confirmed to her that the president "did not want to drive to honor American war dead" at the Aisne-Marne cemetery outside Paris, implying weather was not a factor.

One official also told her that Trump had used the word "suckers" to denigrate the military, but in a different context related to the Vietnam War.

"When the President spoke about the Vietnam War, he said, 'It was a stupid war. Anyone who went was a sucker,'" she quoted the unnamed official as saying.

"It was a character flaw of the President. He could not understand why someone would die for their country, not worth it," the source said.

A furious Trump tweeted late Friday: "Jennifer Griffin should be fired for this kind of reporting. Never even called us for comment. @FoxNews is gone!"

Trump has furiously defended himself in the wake of the story in The Atlantic, tweeting and retweeting stories condemning it as "fake news." He called the magazine's editor-in-chief Jeffrey Goldberg, who wrote the piece, a "slimeball."

The habitually Trump-friendly Fox News has been criticized for seemingly sidelining Griffin's reporting in its coverage of the story. 

A story on its front page Saturday was headlined: "Sources dispute claim Trump nixed visit to military cemetery over disdain for slain veterans."

Several of Griffin's colleagues at Fox have publicly defended her on Twitter, along with Republican congressman Adam Kinzinger, who called her "fair and unafraid."

"I can tell you that my sources are unimpeachable," Griffin said on-air Saturday on her network. "My sources are not anonymous to me and I doubt they are anonymous to the president."

Just before The Atlantic published its story, a poll by the Military Times and the Syracuse University Institute for Veterans and Military Families found that just 37.4 percent of active duty personnel support Trump's re-election bid, while 43.1 percent back Joe Biden.