The Tomahawk was first used in combat on 17 January 1991, on the opening night of Operation Desert Storm. On that day, for the first time since the surrender of Japan in 1945, an American submarine fired in combat, when 12 Tomahawks were launched by U.S. boats in the eastern Mediterranean. Since then, the Tomahawk has become a staple of American campaigns, seeing use in three wars. It has also been exported to the United Kingdom, which has also fitted it to submarines. The use of the Tomahawk has seen a change in the design of attack submarines. The Tomahawk can be fired through 21-inch torpedo tubes, but the and s since have been fitted with vertical launch systems to enable them to carry more of the weapons.