Joe Biden, the frontrunner in the Democratic primary race, has sought to dismiss a media report that he told a war story on the campaign trail strewn with false and inaccurate details.

The former US vice president jumbled elements of multiple events in his tale about a navy captain rejecting a silver star for retrieving the body of a dead comrade, according to the Washington Post.

“In the space of three minutes, Biden got the time period, the location, the heroic act, the type of medal, the military branch and the rank of the recipient wrong, as well as his own role in the ceremony,” the Post said.

Biden relayed the story at a town hall event last week in Hanover, New Hampshire. He recounted how a “young Navy captain” rappelled down a 60ft ravine in the mountains in the Kunar province of Afghanistan during an unsuccessful attempt to retrieve a fellow soldier’s body.

Biden claimed that a general wanted him to fly to Afghanistan to pin a silver star on the captain but the captain declined. “God’s truth, my word as a Biden,” the former vice president said. “He stood at attention, I went to pin him, he said: ‘Sir, I don’t want the damn thing. Do not pin it on me sir, please. Do not do that. He died. He died.’”

But based on interviews with more than a dozen troops, commanders and Biden campaign officials, the Washington Post said it found that he apparently conflated elements of at least three actual events into one story.

“Biden visited Kunar province in 2008 as a US senator, not as vice-president,” the paper reported. “The service member who performed the celebrated rescue that Biden described was a 20-year-old Army specialist, not a much older Navy captain.

“And that soldier, Kyle J White, never had a Silver Star, or any other medal, pinned on him by Biden. At a White House ceremony six years after Biden’s visit, White stood at attention as President Barack Obama placed a Medal of Honor, the nation’s highest award for valor, around his neck.”

Campaigning in South Carolina on Thursday, Biden did not offer an apology or admit error. “I don’t understand what they’re talking about, but the central point is it was absolutely accurate what I said,” he told the Charleston Post and Courier. “He refused the medal. I put it on him, he said, ‘Don’t do that to me, sir. He died. He died.’ ”

The candidate denied “that there’s anything I said about that that wasn’t the essence of the story. The story was that he refused the medal because the fella he tried to save – and risked his life saving – died. That’s the beginning, middle and end. The rest of you guys can take it and do what you want with it.”

Biden, 76, is a self-confessed “gaffe machine” with a long career of blunders, including during two previous failed presidential campaigns. Some commentators argue this again makes him vulnerable against Democratic challengers for 2020.

David Axelrod, the former Barack Obama campaign strategist, tweeted on Thursday: “Not in any way taking anything away from the reporters, who undoubtedly reported it out, but this reads like the product of a pretty sophisticated opposition research dump … And there will be more, because @JoeBiden is a gaffe and embellishment machine. But if you read to the end of this story, it also reflects something that is a real strength, and that is his empathy.”