Turkey has participated in NATO operations and peacekeeping missions, contributing to the KFOR and the UN police mission in Kosovo (UNMIK), as well as the EU-led police mission "Proxima" in the Republic of North Macedonia. Turkey is also contributing to the EUFOR-ALTHEA. For the reconstruction efforts Turkey is part of launching the South-East European Cooperation Process (SEECP), and the Multinational Peace Force Southeast Europe (MPFSEE)/Southeastern Europe Brigade (SEEBRIG). Turkey also plays a role in regional economic initiatives as well as the Stability Pact for Southeastern Europe initiated by the EU and the Southeast European Cooperative Initiative (SECI). Turkey is a founding member of the UN (1945), the Organisation for Economic Co-operation and Development (1961), the Organisation of Islamic Cooperation (1969), the Organization for Security and Co-operation in Europe (OSCE) (1973), and the G20 industrial nations (1999). Turkey is a member state of the Council of Europe (1949) and NATO (1952) as well as being in full accession negotiations with the European Union since 2005, having been an associate member since 1963. Turkey was also an associate member of the Western European Union from 1992 to 2011, and signed the E.U. Customs Union agreement in 1995. Turkey entered NATO in 1952 and serves as the organization's vital eastern anchor, controlling the Turkish Straits which lead from the Black Sea to the Mediterranean and sharing a border with Syria, Iraq, and Iran. A NATO headquarters is located in İzmir, and the United States has maintained air forces at the Incirlik Air Base in the province of Adana. Turkey is also a member of the World Trade Organization (WTO) since 1995. It has signed free trade agreements with the European Free Trade Association (EFTA), Israel, and many other countries. In 1992, Turkey and 10 other regional nations formed the BSEC to expand regional trade and economic cooperation.