CANNES, France (AP) - Veteran American newsman Pierre Salinger said today he has a government document saying that Navy gunners accidentally shot down TWA Flight 800 while conducting missile tests, killing all 230 people aboard.

Salinger, an ABC News correspondent from 1978-83 and former spokesman for President Kennedy, said he was willing to give the FBI the document and its ``very important details that show the plane was brought down by a U.S. Navy missile.''

The Navy and FBI denied Salinger's charge. Investigators have yet to pin down whether a missile, mechanical failure or a bomb caused the July 17 explosion that brought down the Paris-bound plane shortly after it left New York's Kennedy Airport.

Salinger told reporters the document showed the Navy was testing missiles off the coast of New York, and had been told planes would be flying higher than 21,000 feet. The Navy was unaware that Flight 800 was flying at 13,000 feet because another commercial plane was flying above it, he said.

FBI Assistant Director James Kallstrom, who is heading the criminal probe, said investigators ``have looked at this thoroughly and we have absolutely not one shred of evidence that it happened or it could have happened.''

Kallstrom urged Salinger to give the document to the FBI ``as soon as possible.''

Asked if he was prepared to hand it over, Salinger said: ``Yes I am.'' He said the FBI had yet to contact him directly, although he said agents had visited his house in Washington. He said he planned to spend the weekend in Paris, then travel to Boston on Tuesday.

Salinger, vice chairman of Burson-Martsteller, a Washington-based public relations firm, first made his story public at an aviation conference in this Riviera city on Thursday. ``The truth must come out,'' he told some 150 executives of the Air Promotion Group. About 40 airlines, including American carriers, are linked to the group.

This morning, he sat with reporters in the lobby of the seaside Carlton Hotel and displayed two crumpled pages which he said was the document he received five weeks earlier. He would not let reporters read the document.

``The original document was written by an American but it was given to me by someone in French intelligence in Paris,'' he said. The American ``was tied to the U.S. Secret Service, and has important contacts in the U.S. Navy.'' He refused to elaborate.

Salinger said the document was dated Aug. 22 and was posted on the Internet at the beginning of September.

The FBI has received dozens of calls from people claiming to have seen a missile at the time of the explosion. Rumors that the aircraft was shot down by friendly fire also have abounded on the Internet.

Salinger said he decided to go public with the document after the media ignored a story in Paris Match magazine last week that examined the missile theory.

Salinger said ``some very important people'' he showed the document to had told him to wait until after Tuesday's U.S. elections because officials ``probably won't tell the truth until after the American election.''

``If the news came out that an American naval ship shot down that plane it would be something that would make the public very very unhappy and could have an effect on the election,'' he said.

Asked, however, if he thought the White House knew about the information and covered it up, he said: ``No. I have no idea.''

Lt. Cmdr. Rob Newell, a Navy spokesman at the Pentagon, said the Navy's only aircraft in the area at the time of the crash was a P-3 Orion anti-submarine plane, which does not carry missiles.

He said the nearest warship, the USS Normandy, an Aegis-type missile cruiser, was 185 miles to the south and ``couldn't even see the TWA plane.''

Salinger, when asked what type of ship was involved, told New York radio station WCBS it was a ``ship known as the P-3, but I don't know what that means.'' He said it was based in Norfolk, Va.