NEW YORK, October 2 / RIA "Novosti" Andrey Loshchilin /. For the first time in history, oil trading on the New York Mercantile Exchange ended at a mark exceeding $50 per barrel. On Friday, the closing price there was $50.12, which is 48 cents more than the corresponding figure on Thursday. The rise in quotations was pushed by new fears about the situation in Nigeria, which is the largest oil producer in Africa, extracting 2.3 million barrels per day. For several hours, uncertainty persisted regarding whether the government and rebels intended to observe the ceasefire agreement in the Niger River delta concluded two days earlier. The tension subsided only after President Olusegun Obasanjo ordered the country's air force planes and helicopters to leave the area. Last Tuesday, when the leader of the rebels seeking autonomy and a share in oil revenues, Mujahid Dokubo-Asari, threatened to launch large-scale combat operations in the Niger delta, the price of oil in New York reached an absolute maximum in the entire 21-year history of oil contract conclusion there - $50.47. After the conclusion of the truce, quotations began a cautious downward movement.