ALGIERS  - OPEC President Chakib Khelil warned Sunday that oil prices will continue to rise because of the falling dollar, in an interview in Algeria-News. "The price of oil will rise again in the coming weeks. We have to follow the evolution of the dollar, because a one percent fall in the dollar means four dollars more on the price of oil," Khelil, who is Algeria's minister of energy and mines, told the independent daily. "As producer countries we think that the current supply is sufficient, that this balance in supply is in everybody's interests and that it shouldn't be disturbed, because the current rise in oil prices is in nobody's interest," the head of the Organisation of Petroleum Exporting Countries stressed. He also commented on the geopolitical effects on the price of oil, notably the crisis between Iran and the West over its nuclear programme and rejected the theory that oil cartel members were against boosting production to put a downward pressure on prices. "I believe that 60 per cent of the rise is due to the fall in the exchange rate of the dollar and to geopolitical problems, and 40 percent to the intrusion of bioethanol on the market," he said. "I can affirm that all the (OPEC) countries are in favour of new explorations (of oil reserves), but the fact is that the embargo imposed by Libya has prevented any increase of investment in that country, just as the current embargo on Iran is stopping anyone investing there," Khelil said. "The United States is threatening severe economic sanctions against any group which dares invest in Iran. Similarly, the war in Iraq is why investment there is weak. No OPEC country can invest in embargoed countries." Meanwhile, despite record crude prices, the major oil companies are struggling to access resources that are being jealously guarded by national companies with whom they are forced to establish partnerships. As paradoxical as it may seem, high oil prices do not mean a golden age for the likes of ExxonMobil, Chevron, Totalor BP. Of course, with a barrel of oil at more than 140 dollars, they are seeing major profits, but the future has never seemed so uncertain. The problem is access to reserves. The oil majors now control less than 10 percent of world resources of gas and oil, against 70 percent in the 1970s, according to figures released by the office of Ernst and Young.  at the World Petroleum Congress in Madrid. As a result they are being forced to explore in increasingly extreme conditions.