The International law bearing on issues of Arab–Israeli conflict, which became a major arena of regional and international tension since the birth of Israel in 1948, resulting in several disputes between a number of Arab countries and Israel. There is an international consensus that some of the actions of the states involved in the Arab–Israeli conflict violate international law, but some of the involved states dispute this. In the Six-Day War in 1967, Israel pre-empted what many Israeli leaders believed to be an imminent Arab attack and invaded and occupied territory that had itself been invaded and occupied by neighboring Egypt, Syria and Jordan in the 1948 Arab–Israeli War. Following the peace treaties between Israel and Egypt and Israel and Jordan, in which the states relinquished their claims to the Israeli-occupied territory, the conflict today mostly revolves around the Palestinians. The main points of dispute (also known as the "core issues" or "final status issues") are the following: Israel's annexation of East Jerusalem (Israel has also annexed the Golan Heights, but that territory isn't claimed by Palestinians), construction of Israeli settlements in the Palestinian territories and the erection of the Israeli West Bank barrier; how borders should be decided between Israel and a Palestinian state; the right of return of the Palestinian refugees from the 1948 and 1967 wars. Customary international law Unlike a treaty agreement, customary international law is usually not written. Customs of a longstanding nature can be codified by formal treaties. The Laws and Customs of War on Land (Hague Convention IV) of 18 October 1907 and the Geneva Conventions of 12 August 1949 are examples of conventional laws that are declarations of customary law. To prove that a certain rule is customary one has to show that it is reflected in state practice and that there exists a conviction in the international community that such practice is required as a matter of law. In this context, "practice" relates to official state practice and therefore includes formal statements by states. A contrary practice by some states is possible because if this contrary practice is condemned by the other states, or subsequently denied by the government itself, the original rule is actually confirmed. In accordance with article 13 of the UN Charter, the General Assembly is obligated to initiate studies and to make recommendations that encourage the progressive development of international law and its codification. Acting in that