Beginning at the end of the 1967 war until the 1990s, Israel administered the West Bank and the Gaza Strip. The Golan Heights, captured from Syria during the same war, was annexed in 1981; the Sinai Peninsula, taken from Egypt, was restored to Egyptian sovereignty in 1983, in accordance with a 1979 peace treaty. In 1994 Israel returned small pockets of some of the land captured in the war, to be administered in a less than totally sovereign fashion, by the Palestinian Authority. The move was in accord with a peace agreement (the Israel-PLO Declaration of Principles on Interim Self-Government Arrangements or DOP) signed in Washington, DC, on 13 September 1993 by representatives of Israel and the Palestine Liberation Organization (PLO). In January 1996, a Palestinian Legislative Council was elected to form the foundation for the interim self-government for the West Bank and Gaza Strip. In May 1994, a new agreement (the Israel-PLO 4 May 1994 Cairo Agreement on the Gaza Strip and the Jericho Area) transferred responsibility for the Gaza Strip and Jericho to the Palestinians. Over the next several years, agreements between Israel and the PLO transferred responsibility for West Bank territory from Israel to Palestinian control. According to the terms of the DOP, Israel was to continue to provide security for the territories transferred to Palestinian control during the period of transition. In 1999, negotiations to set the terms for permanent status for the West Bank and Gaza began, but a number of factors—continuing expansion of Israeli settlements in territory transferred to Palestinian control, outbreaks of violence and terrorism beginning in 2000 and continuing for the next two years, instability in the Palestinian Authority, and severe reaction on the part of the Israeli military—combined to undermine further progress. The estimated population of the West Bank in 2002 was 2,163,667, not including an estimated 187,000 Israeli settlers; the estimated population of the Gaza Strip that year was 1,225,911, not including an estimated 5,000 Israeli settlers.