In 1990, after the Iraqi invasion of Kuwait, Italy joined the coalition forces, and for the first time in 45 years Italian pilots and aircraft were assigned to combat operations. Needing to replace the obsolete F-104 Starfighters, Italy joined with Germany, Spain and the United Kingdom in the development of the Eurofighter Typhoon, which was expected to enter the Italian Air Force in 2000. In 1994, with the Typhoon still some years from introduction to service, 24 Panavia Tornado Air Defense Variant (ADV) interceptors were leased from the United Kingdom for a period of 10 years. The ADV Tornados served as fighter-interceptors to supplement and then to replace the old F-104 Starfighters. However, delays in the production of the Typhoon forced the Italians to seek a supplement, and then replacement, for the leased Tornado ADVs. With the UK lease due to expire in 2004, the Italian government wished to avoid a costly lease extension and instead opted to lease 34 F-16 Fighting Falcon multi-role fighter planes on multi-year leases from the US. The last of these fighters was returned to the United States in May 2012, following the Italian Air Force's acquisition of a sufficient number of Typhoons over a period of several years. The Typhoons are intended to replace all of the F-104, Tornado ADV and F-16 aircraft. The last of the Italian F-104s was withdrawn from service in 2004.