Kuwait is a small, oil-rich country nestling at the top of the Gulf, flanked by large or powerful neighbors - Saudi Arabia to the south, Iraq to the north and Iran to the east. With about 8 percent of the world’s total oil reserves, Kuwait is one of the world's leading oil producers. Threatened in the 19th century by the Ottoman Turks and various powerful Arabian Peninsula groups, in 1899 Kuwait signed an agreement with Britain to oversee its foreign relations and defense. In 1961 Kuwait gained independence from Britain. Kuwait's northern border with Iraq dates from an agreement reached with Turkey in 1913. Iraq accepted this claim in 1932 upon its independence from Turkey. But following Kuwait's independence, Iraq immediately claimed Kuwait, arguing that Kuwait had been part of the Ottoman Empire subject to Iraqi suzerainty. In 1963, Iraq reaffirmed its acceptance of Kuwaiti sovereignty and the boundary it agreed to in 1913 and 1932. In August 1990, Iraq attacked and invaded Kuwait. Following several weeks of aerial bombardment, a United Nations-mandated coalition led by the United States began a ground assault in February 1991 that liberated Kuwait. Following liberation, the UN demarcated the Iraq-Kuwait boundary on the basis of the 1932 and the 1963 agreements between the two states. In November 1994, Iraq formally accepted the UN-demarcated border with Kuwait. Kuwait is a constitutional, hereditary emirate ruled by princes (Amirs) who have been drawn from the Al Sabah family since the middle of the 18th century. The 1962 constitution provides for an elected National Assembly, which has often clashed with the ruling family. The country has also faced violence from militant Islamists.