An Italian navy crew in the Persian Gulf "distinctly heard" the USS Vincennes warship issue a warning to an Iranian passenger jet carrying 290 people before shooting down the plane, the frigate's commander said Monday.

Italian military sources also said the American warship, in radio messages immediately after the tragic incident Sunday, told other ships in the area that it had shot down an Iranian F-14. The United States claims the Vincennes' captain mistook the Iran Air jet for a fighter plane.In the worst incident of its kind in aviation history, a French-built Airbus A-300 was blown out of the sky over the gulf Sunday by missile fire from the American warship, which was engaged in renewed sea battles with Iran.

"We distinctly heard a U.S. ship send a

warning signal to a plane that was approaching it," Adm. Angelo Mariani said in an interview broadcast on state-run Italian television.

Mariani, commander of Italy's gulf squadron, said he and his crew heard the warning once while on their frigate Espero, which had just crossed the Strait of Hormuz where the incident occurred.

Military sources said the Espero had just escorted the Italian merchant ship Jolly Smeraldo through the strait to Dubai in the United Arab Emirates - ironically, the Iranian passenger jet's destination.

The Italian news agency ANSA quoted Mariani as saying that the Vincennes put out the warning message on an emergency frequency for military use.

Mariani, saying his ship was 70 miles from the site of the incident, when it took place, said the American vessel may have sent other warnings that his frigate did not receive.