The head of the International Energy Agency Fatih Birol said on Thursday the United States would - in the long term - become the "undisputed leader of oil and gas production worldwide."

Speaking at the U.N. climate conference in Bonn, Germany, he said the agency expected oil markets to rebalance next year if oil demand remained "more or less" as robust as it is today and if OPEC and non-OPEC continued with their oil production cuts.