Greece is a charter member of the UN, having joined on 25 October 1945, and participates in ECE and all the nonregional specialized agencies. Greece was admitted to NATO in 1951 but suspended its military participation (1974–80) because of the Cyprus conflict. It belongs to the Council of Europe and OECD and is a signatory of the Law of the Sea and a member of the WTO. Greece is also a permanent observer at the OAS. The country, which had been an associate member of the EU, became a full member as of 1 January 1981. In August 1987, Greece and Albania signed a pact ending the state of war that had existed between them since World War II (1939–45).