Iran's nuclear program began as a result of the Cold War alliance between the United States and the Shah of Iran, Mohammad Reza Pahlavi, who emerged as an important US ally in the Persian Gulf. Under the Atoms for Peace program, Iran received basic nuclear research facilities from the United States. In return, Tehran signed the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) in 1968. Fueled by high oil prices in the 1970s, Iran sought to purchase large-scale nuclear facilities from Western suppliers in order to develop nuclear power and fuel-cycle facilities with both civilian and potential military applications. In March 1974, the shah established the Atomic Energy Organization of Iran (AEOI). Sensing a heightened risk of nuclear proliferation, the United States convinced Western allies to limit the export of nuclear fuel-cycle facilities to Iran. Supreme Leader Ayatollah Ruhollah Khomeini, whose revolution displaced the Shah's monarchy in 1979 and ruled the newly established Islamic Republic of Iran until his death in 1989, placed little emphasis on nuclear weapons development because it was viewed as a suspicious Western innovation. During that time, many of Iran's top scientists fled the country while the United States organized an international campaign to block any nuclear assistance to Iran.