The treaty resulted from a diplomatic conference held in Cape Town, South Africa in 2001. The conference was attended by 68 countries and 14 international organizations. 53 countries signed the resolution proposing the treaty. The treaty came into force on 1 April 2004, and has been ratified by 57 parties. The Aircraft Protocol (which applies specifically to aircraft and aircraft engines) took effect on 1 March 2006 when it was ratified by 8 countries: Ethiopia, Ireland, Malaysia, Nigeria, Oman, Panama, Pakistan, and the United States.