Iran is still searching for the ``black box'' recorder that may hold important information about the flight of a jetliner shot down by a U.S. warship, the Iranian navy commander said Monday. Commodore Mohammed Hussein Malekzadegan spoke after the English-language Dubai newspaper Khaleej Times, quoting salvage experts it did not identify, said Iranian frogmen recovered the flight recorder in the Persian Gulf ``a couple of days ago.'' Malekzadegan said in an interview on Tehran radio the black box ``may have been destroyed'' when missiles fired by the cruiser USS Vincennes hit the Iran Air Airbus on July 3, killing all 290 people aboard. ``It's also possible that we may find it,'' he said. ``In any case, the search is continuing.'' Data in the recorder could help determine whether the Airbus A300 received radio warnings from the Vincennes. The Pentagon says the jetliner did not respond to warnings and the cruiser's radar operators mistook the plane for an F-14 fighter because it seemed to be emitting military-type responses. American officials have backed away from earlier claims that the plane was descending or was outside civilian flight lanes. The Khaleej Times said the salvage experts it quoted had worked with Iran in the past and expressed surprise that recovery of the black box had not been announced. It also quoted Itay's commander in the gulf, Rear Adm. Angelo Mariani, as saying the heavy air and sea traffic could complicate investigations of the tragedy. ``There are so many boats, small and big ships, airliners, military jets of various kinds,'' he said. Mariani said the Italian frigate Espero heard a U.S. warship, not identified, radio at least one warning to an aircraft shortly before the Airbus was shot down, the Khaleej Times said. ``Since we only listen to military frequencies, I cannot confirm whether the same message was repeated on the civilian international frequency or not, but I assume it must have been,'' he was quoted as saying. Pentagon spokesmen said repeated warnings were sent on military and civilian channels. In London, the Sunday Times said a British intelligence report based on monitored radio communications is ``severely critical'' of the U.S. Navy for shooting the airliner down. According to the Times, the report says Iran Air Flight 655 left Bandar Abbas for Dubai only three minutes late, was on the correct flight path and was climbing when the missiles struck. It said the report suggested a skirmish with armed Iranian speedboats in which the shooting started July 3 may have been provoked by U.S. helicopters entering Iranian air space. The Vincennes and the USS Elmer Montgomery destroyed two boats and damaged one before the cruiser shot the plane down. The U.S. Navy was escorting the year's 46th convoy of U.S.-flagged Kuwaiti tankers Monday, moving up the gulf to the sheikdom. The 294,739-ton products carrier Townsend was accompanied by the frigate Robert G. Bradley, said a spokesman at U.S. Central Command headquarters in Tampa, Fla. Eleven Kuwait-owned tankers have been given U.S. registraton so the Navy can protect them. Convoys began in July 1987. A Navy investigation of the Airbus disaster was in its sixth day Monday and the Vincennes was anchored off Bahrain with two barges alongside. Its crew has been restricted to the ship for security reasons, with sailors allowed ashore only in small groups to make telephone calls home.