Operation Praying Mantis was an attack on April 18, 1988, by U.S. naval forces within Iranian territorial waters in retaliation for Iranian mining of the Persian Gulf during the Iran-Iraq War and the subsequent damage to an American warship. On April 14, the guided missile frigate USS Samuel B. Roberts struck a mine while deployed in the Persian Gulf as part of Operation Earnest Will, the 1987-88 convoy missions in which U.S. warships escorted reflagged Kuwaiti oil tankers to protect them from Iranian attacks. The explosion blew a 25-foot (7.6-meter) hole in the Roberts's hull and nearly sank it, but the crew saved their ship with no loss of life, and Roberts was towed to Dubai on April 16. After the mining, U.S. Navy divers recovered other mines in the area, and when the serial numbers were found to match those of mines seized along with the Iran Ajr the previous September, U.S. military officials planned a retaliatory operation against Iranian targets in the Persian Gulf. According to the account, the U.S. attack helped pressure Iran to agree to a ceasefire with Iraq later that summer, ending the eight-year conflict between the Persian Gulf neighbors. On November 6, 2003, the International Court of Justice ruled that the actions of the United States of America against Iranian oil platforms on October 19, 1987, in Operation Nimble Archer and on April 18, 1988, in Operation Praying Mantis could not be justified as measures necessary to protect the essential security interests of the United States of America, but it dismissed Iran's claim that the attack by the United States Navy was a breach of the 1955 Treaty of Amity between the two countries. This battle was the largest of the five major U.S. surface engagements since the Second World War and marked the U.S. Navy's first exchange of anti-ship missiles by ships. Following the attack on the IS Sabalan, U.S. naval forces were ordered to assume a de-escalatory posture, giving Iran a way out and avoiding further combat; Iran accepted the offer and combat ceased, though both sides remained on alert and near-clashes occurred through the night and into the next day as the forces steamed within the Gulf. Two days after the battle, the USS Lynde McCormick (DG 8) was directed to escort a U.S. oiler out through the Strait of Hormuz while a Scandinavian-flagged merchant remained near, probably for protection, and although the ships remained alert, no hostile indications were received and the clash was over.