||In 2003 the United States, asserting that Iraq was still concealing weapons of mass destruction and alleging links with terrorist groups such as al Qaeda, demanded military action against the Iraqi regime. Unable to obtain UN backing to overthrow the regime of Saddam Hussein, the United States pressed ahead with a 'coalition of the willing': the chief participants were the United States, Britain, and Australia. The Second Gulf War commenced on about 19 March 2003.
In early 2004, Australia still had 850 personnel in the Middle East. HMAS Melbourne was in the Persian Gulf, while RAAF C-130 Hercules and P-3 Orion aircraft were operating in the region. RAAF air traffic controllers remained at Baghdad airport, and soldiers provided security for Australian diplomatic and government personnel. Australians were also helping train the new Iraqi armed forces.
Operation Falconer commenced on 18 March 2003. Operation Catalyst replaced it commencing on 16 July 2003 and running through until 31 July 2009 when almost all Australian troops were withdrawn. However, a very small Australian military presence continued through Operation Kruger (1 Jan. 2009 9 Aug. 2011) and lastly, Operation Riverbank (21 July 2008 14 Dec. 2013).