of the Persian Gulf states supporting Iraq. Both nations attacked oil tankers and merchant ships, including those of neutral nations, in an effort to deprive the opponent of trade. After repeated Iraqi attacks on Iran's main exporting facility on Khark Island, Iran attacked a Kuwaiti tanker near Bahrain on May 13, 1984, and a Saudi tanker in Saudi waters on May 16. Attacks on ships of noncombatant nations in the Persian Gulf sharply increased thereafter, and this phase of the war was dubbed the "Tanker War." Lloyd's of London, a British insurance market, estimated that the Tanker War damaged 546 commercial vessels and killed about 430 civilian mariners. The largest of attacks were directed by Iran against Kuwaiti vessels, and on November 1, 1986, Kuwait formally petitioned foreign powers to protect its shipping. The Soviet Union agreed to charter tankers starting in 1987, and the United States Navy offered to provide protection for tankers flying the U.S. flag on March 7, 1987. Operation Prime Chance was a United States Special Operations Command operation intended to protect U.S.-flagged oil tankers from Iranian attack. The operation took place roughly at the same time as Operation Earnest Will, the largely Navy effort to escort the tankers through the Persian Gulf. Under international law, an attack on such ships would be treated as an attack on the U.S., allowing the U.S. to retaliate militarily. This support would protect ships headed to Iraqi ports, effectively guaranteeing Iraq's revenue stream for the duration of the war. Special Operations Forces also assisted in this effort. The 160th Special Operations Aviation Regiment operated AH-6 helicopters from a large barge anchored at sea. A second platform was flown by Special Forces from Fort Bragg, piloting OH-58Ds. "These things looked extremely sinister. They were all black and bristling with antennas and had a huge round sight module about two feet in diameter stuck on a mast above the rotor blades. ... The impression you got, just looking at one of these things on the ground, was of a giant insect staring at you before you die", a Special Forces officer is quoted as saying. On April 14, 1988, the frigate USS Samuel B. Roberts was badly damaged by an Iranian mine. U.S. forces responded with Operation Praying Mantis on April 18, the United States Navy's largest engagement of surface warships since World War II. Two Iranian ships were destroyed, killing