NBC News anchor Brian Williams conceded Wednesday that a story he told repeatedly about being under fire while covering the Iraq war in 2003 was false.

"I want to apologize," he said on air Wednesday.

He said he was not on a helicopter that was hit by enemy fire and forced down more than a decade ago - a story he retold as recently as last week during a televised tribute to a retired soldier during an NHL game.

Instead, Williams told the military newspaper Stars & Stripes in a story published Wednesday that he "misremembered" the story and was sorry for repeating it.

His admission came after Stars & Stripes contacted crew members of the Chinook helicopter that the anchorman had said he was in when it was hit by two rockets and small-arms fire. They said that Williams was not aboard the aircraft during the incident at the start of the war. They said Williams arrived on another, undamaged helicopter an hour after the crippled Chinook had landed.

"I would not have chosen to make this mistake," Williams told the newspaper. "I don't know what screwed up in my mind that caused me to conflate one aircraft with another."

Williams' claim of surviving an attack bothered several soldiers familiar with air operations at the time, including Sgt. First Class Joseph Miller, who was the flight engineer on the helicopter that carried the NBC News crew. "No, we never came under direct enemy fire to the aircraft," he told the newspaper.

Soldiers' complaints led Williams to apologize.

"I spent much of the weekend thinking I'd gone crazy," Williams wrote in an apology to the soldiers that was posted on NBC Nightly News' Facebook page. "I feel terrible about making this mistake.. . ."

Stars & Stripes interviewed several soldiers who said they recalled NBC's reporting that Williams was aboard the aircraft that was attacked. Stars & Stripes found an NBC News story from March 26, 2003, with the headline "Target Iraq: Helicopter NBC's Brian Williams Was Riding In Comes Under Fire."