The geographical extreme points of Croatia are Žabnik in Međimurje County as the northernmost point, Rađevac near Ilok in Vukovar-Syrmia County as the easternmost point, Cape Lako near Bašanija in Istria County as the westernmost point and the islet of Galijula in Palagruža archipelago in Split-Dalmatia County as the southernmost point. On the mainland, Cape Oštra of the Prevlaka peninsula in Dubrovnik-Neretva County is the southernmost point. Italy and Yugoslavia defined their delineation of the continental shelf in the Adriatic Sea in 1968, with an additional agreement on the boundary in the Gulf of Trieste signed in 1975 in accordance with the Treaty of Osimo. All the successor states of former Yugoslavia accepted the agreements. Prior to Yugoslavia's break-up, Albania, Italy and Yugoslavia initially proclaimed territorial waters, subsequently reduced to the international-standard ; all sides adopted baseline systems. Croatia also declared its Ecological and Fisheries Protection Zone (ZERP)—a part of its Exclusive Economic Zone—as extending to the continental shelf boundary. Croatia's territorial waters encompass ; its internal waters located within the baseline cover an additional . Croatia and Slovenia started negotiations to define maritime borders in the Gulf of Piran in 1992 but failed to agree, resulting in a dispute. Both countries also declared their economic zones, which partially overlap. Croatia's application to become an EU member state was initially suspended pending resolution of its border disputes with Slovenia. These were eventually settled with an agreement to accept the decision of an international arbitration commission set up via the UN, enabling Croatia to progress towards EU membership. The dispute has caused no major practical problems in areas other than the EU membership negotiations progress, even before the arbitration agreement. The maritime boundary between Bosnia–Herzegovina and Croatia was formally settled in 1999, but a few issues are still contested—the Klek peninsula and two islets in the border area. The Croatia–Montenegro maritime boundary is disputed in the Bay of Kotor, at the Prevlaka peninsula. The situation was exacerbated by the peninsula's occupation by the Yugoslav People's Army and later by the Serbian-Montenegrin army, which in turn was replaced by a United Nations observer mission that lasted until 2002. Croatia took over the area with an agreement that allowed Montenegrin presence in Croatian waters in the bay, and the dispute has become far less contentious since the independence of Montenegro in 2006.