The Republic of the Marshall Islands signed the Mine Ban Treaty on 4 December 1997, but has still not ratified. It was absent from the vote on UN General Assembly Resolution 56/24M in November 2001, calling for universalization of the Mine Ban Treaty. The Marshall Islands was the only treaty signatory to abstain from voting on similar pro-ban UNGA resolutions in 1998, 1999, and 2000. One possible reason for these abstentions and for the lack of ratification could be the close economic, political and military dependence between the Marshall Islands and non-signatory, the United States, as defined by the Compact of Free Association. The Marshall Islands is not believed to have ever produced, transferred, stockpiled or used antipersonnel mines. There are considerable quantities of UXO left over from World War II when Japanese and American forces fought over many of the islands.