as a political union, the EU has no border disputes with neighboring countries, but Estonia has no land boundary agreements with Russia, Slovenia disputes its land and maritime boundaries with Croatia, and Spain has territorial and maritime disputes with Morocco and with the UK over Gibraltar; the EU has set up a Schengen area - consisting of 22 EU member states that have signed the convention implementing the Schengen agreements or "acquis" (1985 and 1990) on the free movement of persons and the harmonization of border controls in Europe; these agreements became incorporated into EU law with the implementation of the 1997 Treaty of Amsterdam on 1 May 1999; in addition, non-EU states Iceland and Norway (as part of the Nordic Union) have been included in the Schengen area since 1996 (full members in 2001), Switzerland since 2008, and Liechtenstein since 2011 bringing the total current membership to 26; the UK (since 2000) and Ireland (since 2002) take part in only some aspects of the Schengen area, especially with respect to police and criminal matters; nine of the 13 new member states that joined the EU since 2004 joined Schengen on 21 December 2007; of the four remaining EU states, Romania, Bulgaria, and Croatia are obligated to eventually join, while Cyprus' entry is held up by the ongoing Cyprus dispute
1997 boundary delimitation treaty with Belarus remains unratified due to unresolved financial claims, stalling demarcation and reducing border security; delimitation of land boundary with Russia is complete and demarcation began in 2012; the dispute over the boundary between Russia and Ukraine through the Kerch Strait and Sea of Azov is suspended due to the occupation of Crimea by Russia; Ukraine and Moldova signed an agreement officially delimiting their border in 1999, but the border has not been demarcated due to Moldova's difficulties with the break-away region of Transnistria; Moldova and Ukraine operate joint customs posts to monitor transit of people and commodities through Moldova's Transnistria Region, which remains under the auspices of an Organization for Security and Cooperation in Europe-mandated peacekeeping mission comprised of Moldovan, Transnistrian, Russian, and Ukrainian troops; the ICJ ruled largely in favor of Romania in its dispute submitted in 2004 over Ukrainian-administered Zmiyinyy/Serpilor (Snake) Island and Black Sea maritime boundary delimitation; Romania opposes Ukraine's reopening of a navigation canal from the Danube border through Ukraine to the Black Sea
