Inquiry Into U.S. Account of Iran Jet Downing Sought : Military: Nunn asks Pentagon to determine if incident was part of U.S. covert operation to aid Iraq during war with Iran.

The chairman of the Senate Armed Services Committee has called for a Pentagon investigation into whether Congress was misled by the official account of the downing of an Iranian commercial airliner by a Navy cruiser four years ago.

Sen. Sam Nunn (D-Ga.) is asking the Pentagon to determine whether the shooting down of the passenger jet occurred during covert operations by the Navy designed to provoke Iranian attacks as part of a U.S. effort to assist Iraq in the final stages of the Iran-Iraq War.

“I believe that it is very important that there be an expeditious inquiry into these serious allegations and that a full-blown investigation be conducted if merited,” Nunn said in a letter to Defense Secretary Dick Cheney. The letter was released Friday by Nunn’s office.

The cruiser Vincennes shot down the Iranair plane on July 3, 1988, killing all 290 people on board. At the time, the jet was on a scheduled flight within a commercial air corridor, but Navy officers said they mistook it for an attacking jet fighter.

Officials of the Ronald Reagan Administration said in 1988 that the Vincennes was in international waters when it fired on the aircraft. George Bush, then vice president, told the United Nations that the incident occurred during “a naval attack initiated by Iranian vessels against a neutral vessel and subsequently against the Vincennes.”

A statement issued by the Pentagon this week acknowledged that the Navy vessel was in Iranian territorial waters at least part of the time during the incident. The statement said the Vincennes was engaged in defense maneuvers at the time.

Nunn called for the investigation after questions were raised in a joint news report by ABC News’ “Nightline” program and Newsweek magazine Wednesday night. During the broadcast, Adm. William J. Crowe, chairman of the Joint Chiefs of Staff in the Reagan Administration, was quoted as confirming that the Vincennes was in Iranian waters when it shot down the passenger plane.

Saying that the new charges “raise serious allegations that the Administration deliberately misled Congress,” Nunn asked the Pentagon to review its files and to question the two top naval officials who oversaw the Gulf operation, Adm. Robert J. Kelly and Vice Adm. Anthony A. Less.

Capt. Will Rogers, commander of the Vincennes at the time, insisted Thursday night that his vessel was in international waters when the incident occurred. In an interview on CNN, Rogers said he was shocked by Crowe’s statement and repeated his belief at the time that the Iranian airliner was an attacking jet fighter.

Rogers, who retired from the Navy last year, has written a book about the incident and its aftermath with his wife, Sharon. She escaped serious injury when a bomb blew up her van in San Diego shortly after the downing of the airliner. Investigators originally suspected terrorists, but the case has never been solved, and as the inquiry went on, they increasingly doubted that terrorists were involved.

The Vincennes was part of an American naval force dispatched to the Gulf to protect oil tankers and other neutral vessels from Iranian gunboats. The ABC-Newsweek report suggested that the Americans were ordered to provoke incidents with Iran as part of the Reagan Administration’s efforts to help Iraq. The result, said the report, was a tense atmosphere in which the Vincennes mistakenly downed the civilian airliner.

While the Administration was publicly neutral in the Iran-Iraq War, subsequent information has shown that the U.S. government assisted Iraq in numerous ways in an effort to stop Iran from winning the war, which ended with a cease-fire in August, 1988.

As part of those efforts, a former senior Reagan Administration official who was involved in the policy told The Times in a recent interview that Navy SEAL commandos blew up Iranian oil platforms.

Rogers said he was unaware of any orders to provoke Iran.