 In the early 1980s, the U.S. Navy began development of a new mine countermeasures (MCM) force, which included two new classes of ships and minesweeping helicopters.The vital importance of a state-of-the-art mine countermeasures force was strongly underscored in the Persian Gulf during the eight years of the Iran–Iraq War, and in Operations Desert Shield and Desert Storm in 1990 and 1991 when "Avenger" and "Guardian" conducted MCM operations.