US Navy Iranian frigate IS Sahan after being hit with three Harpoon missiles and cluster bombs by aircraft from USS Enterprise, April 19, 1988. In April 1988, the US attacked Iran in the Persian Gulf in retaliation for the mining of a US ship. Operation Praying Mantis, the largest US naval action since World War II, was brief but deadly. Thirty-three years later, the weapons each side would use have only gotten more destructive. Just before 8:00 a.m. on April 18, 1988, members of Iran’s Islamic Revolutionary Guard Corps Navy (IRGCN) stationed on the Sassan and Sirri oil platforms in the Persian Gulf received a warning from US Navy ships several thousand yards away.