US Vice President Dick Cheney issued a warning to Iran while aboard a US aircraft carrier in the Persian Gulf on Friday, saying the United States would join allies to keep Iran from getting nuclear weapons "and dominating the region." With two US carrier groups now in the region, Chneney declared, "We're sending clear messages to friends and adversaries alike. We'll keep the sea lanes open." Iran exerts considerable control over the narrow passageway that separates the Persian Gulf from the open waters of the Arabian Sea. Roughly a quarter of the world's oil supplies pass through the Straits of Hormuz. Iran loomed about 150 miles to the east as Cheney spoke aboard the USS John C. Stennis. The carrier was steaming about 20 miles off Abu Dhabi in the United Arab Emirates. Cheney is spending time there after a two-day tour of Iraq.