Non-aligned states forged still other forms of economic cooperation as leverage against the superpowers. OPEC, the OAU, and the Arab League had overlapping members, and in the 1970s the Arabs began extending huge financial assistance to African nations in an effort to reduce African economic dependence on the United States and the Soviet Union. However, the Arab League has been torn by dissension between authoritarian pro-Soviet states, such as Nasser's Egypt and Assad's Syria, and the aristocratic-monarchial (and generally pro-Western) regimes, such as Saudi Arabia and Oman. And while the OAU has witnessed some gains in African cooperation, its members were generally primarily interested in pursuing their own national interests rather than those of continental dimensions. At a 1977 Afro-Arab summit conference in Cairo, oil producers pledged $1.5 billion in aid to Africa. Recent divisions within OPEC have made concerted action more difficult. Nevertheless, the 1973 world oil shock provided dramatic evidence of the potential power of resource suppliers in dealing with the more developed world.