TEHRAN, Iran — Iran's Revolutionary Guards have begun a military exercise and issued a warning that Israel and U.S. naval forces in the Persian Gulf would be prime targets if Iran is attacked. The Web site of the elite Iranian force posted a statement late Monday announcing the military drill, which it said involved "missile squads," but did not say where it was taking place. Iran's guards and national army hold regular exercises two or three times a year, but the statement did not say whether this drill was one of them or if it was a special exercise. Israel's military sent warplanes over the eastern Mediterranean for a large military exercise in June that U.S. officials described as a possible rehearsal for a strike on Iran's nuclear facilities, which the West fears are aimed at producing atomic weapons. The Iranian Web Site quoted guard official Ali Shirazi as saying that Israel's coastal metropolis of Tel Aviv and U.S. warships in the Gulf would be among the first targets if Iran comes under attack. "The Zionist regime is pushing the White House to prepare for a military strike on Iran," Shirazi was quoted as saying. "If such a stupidity is done by them, Tel Aviv and the U.S. naval fleet in the Persian Gulf will be the first targets which will be set on fire in Iran's crushing response."