The Queen Elizabeth (U.K.) and Ronald Reagan carrier strike groups, alongside the Iwo ima amphibious ready group (ARG) with 3,000 Marines aboard, conducted a large-scale joint interoperability exercise in the Gulf of Aden on Monday. The combined surface, air and sub-surface exercise was designed to enhance UK, Dutch and US maritime interoperability and demonstrate naval integration through a series of training. the joint communique said. The UK carrier was on its maiden appearance in the drill. The Ronald Reagan strike group included frigates and destroyers armed with guided missiles.