Gaddafi was later infuriated when Egypt and Syria planned the Yom Kippur War against Israel without consulting him, and was angered when Egypt conceded to peace talks rather than continuing the war. Gaddafi become openly hostile to Egypt's leader, calling for Sadat's overthrow, and when Sudanese President Gaafar Nimeiry took Sadat's side, Gaddafi by 1975 sponsored the Sudan People's Liberation Army to overthrow Nimeiry. Focusing his attention elsewhere in Africa, in late 1972 and early 1973, Libya invaded Chad to annex the uranium-rich Aouzou Strip. Offering financial incentives, he successfully convinced 8 African states to break off diplomatic relations with Israel in 1973. Intent on propagating Islam, in 1973 Gaddafi founded the Islamic Call Society, which had opened 132 centres across Africa within a decade. In 1973 he converted Gabonese President Omar Bongo, an action which he repeated three years later with Jean-Bédel Bokassa, president of the Central African Republic.