Salam Fayyad, who resigned as Palestinian prime minister on Saturday, is a US-educated economist widely respected in the West but criticised at home and frustrated by internal wrangling. After weeks of speculation, the bespectacled and immaculately dressed Fayyad quit, disillusioned and worn out from the internal battles of Palestinian politics. Tension flared between president Mahmud Abbas and Fayyad over the stepping down of the Palestinian finance minister, accepted by the premier but rejected by Abbas, with the disagreement causing Fayyad's own resignation, senior officials say. The Revolutionary Council of Abbas's Fatah party had openly criticised Fayyad in April for the first time over his government's economic policies, calling them "improvised and confused." The criticism almost echoed calls from the Palestinian street in September for him to step down during protests over soaring prices. "If a situation arises and I know I am not able to handle it -- for objective reasons and not over complaints -- I want to assure everyone that I will not be an obstacle and will not stay (in office) a day longer," he said at the time. A political independent, the 62-year-old former International Monetary Fund and World Bank official was first appointed premier during the deadly takeover by Islamist movement Hamas -- Fatah's bitter rival -- of Gaza in June 2007. "Hamas gains recognition and is strengthened," Fayyad said in frustration last November, after the movement swapped an Israeli soldier it was holding for the release of more than 1,000 Palestinian prisoners by the Jewish state. At the same time "our people question whether the Palestinian Authority can deliver," he said of the body that governs the West Bank. Hamas has never recognised his authority, continuing instead to recognise its own prime minister, Ismail Haniya, whose national unity government Fayyad's cabinet replaced. Hamas has long insisted that naming a consensus premier would be key to reuniting the Palestinians, who were split into two hostile camps by the Gaza takeover. Fayyad served as finance minister from 2002-2005, and in the last Palestinian unity government between March and June 2007. Initially continuing in that capacity, he developed a plan for rebuilding the impoverished Gaza Strip and reviving Palestinian finances that won pledges of nearly $4.5 billion in aid from international donors at a conference in Egypt in 2009. Under his premiership, the US this year unblocked $500 million in aid to the Palestinian Authority, and Israel unfroze tax revenues it collects on its behalf, following a visit to the region by President Barack Obama. Fayyad is a fluent English speaker who easily quotes Thomas Jefferson, the main author of the American Declaration of Independence, and passionately believes in the principles of transparency and accountability. An articulate advocate of Palestinian rights and hopes, he has also won respect in Israel with the liberal Haaretz newspaper once describing him as "everyone's favourite Palestinian." Fayyad expressed growing frustration with Israel's failure to halt settlement expansion in the occupied West Bank during attempted peace negotiations in 2007. Talks relaunched in 2010 were short-lived and came to an end over the issue. Born in April 1952 in the Tulkarem region of the northern West Bank, Fayyad received a bachelor of science in engineering from the American University of Beirut, and a masters in business administration and a doctorate in economics from the University of Texas. In 1987, he joined the World Bank in Washington, where he worked before becoming the IMF representative in Jerusalem between 1995 and 2001. He also briefly worked at the Arab Bank as its chief representative in the West Bank. He is married and has three children.