Eisenhower, had limited imports of crude and product east of the Rocky Mountains to a percentage of domestic crude production. June 1: Eight OPEC countries raise posted prices by 11.9 percent. June 11: Libya nationalizes Bunker Hunt concession; Nigeria acquires 35 percent participation in Shell-BP concession. June 14: Nixon administration imposes 60-day economy-wide price freeze, superseding Special Rule No. 1 for oil companies. August :Libya nationalizes 51 percent of Occidental Petroleum concession and of the Oasis consortium. August 17: U.S. President Richard Nixon's Cost of Living Council imposes two-tier price ceiling on crude petroleum sales: production of "old" oil (that produced at or below 1972 levels from existing wells) to be sold at March 1973 prices plus 35 cents; production of "new" oil (that produced above 1972 levels from existing wells and oil produced from new wells) to be sold at uncontrolled prices. September 1: Libya nationalizes 51 percent of nine other companies' concessions: Esso, Libya/Sirte, Mobil, Royal Dutch Shell, Gelensberg, Texaco, SoCal, Libyan-American (ARCO), and Grace. September 5: Conference of less developed countries approves forming "producers' associations", calls for withdrawal of Israeli forces from occupied Arab lands. September 15: OPEC supports price hikes and designates six Gulf countries to negotiate collectively with companies over prices. Other members to negotiate individually. September :Kuwait rejects gradual participation increase plan, insists on immediate 60 percent participation. October 6: Beginning of fourth Arab-Israeli War. October 7: Iraq nationalizes Exxon and Mobil shares in Basrah Petroleum Company representing 23.75 percent equity in the company. October 8: OPEC meets with oil companies to discuss revision of 1971 Tehran agreement and oil prices. Negotiations fail. October 16: The Gulf Six (Iran, Iraq, Abu Dhabi, Kuwait, Saudi Arabia and Qatar) unilaterally raise the posted price of Saudi Light marker crude 17 percent from $3.12 to $3.65 per barrel and announce production cuts. October 17: OPEC oil ministers agree to use oil weapon in Arab–Israeli War, mandate cut in exports, and recommend embargo against unfriendly states. October 19: Saudi Arabia, Libya, and other Arab states proclaim an embargo on oil exports to the United States. October 23: Arab oil embargo extended to the Netherlands. November 5: Arab producers announce 25 percent cut in production below September levels. Further cuts of five percent are threatened. November 18: Arab oil ministers cancel the scheduled 5 percent cut in production for EEC. November 23: Arab summit conference adopts open and secret