Oil prices reached a new high of US $70.88 a barrel Tuesday as persistent concerns about Iran's nuclear program and supply disruptions in Nigeria overshadowed a new report from OPEC forecasting weakening global demand. Light, sweet crude for May delivery on the New York Mercantile Exchange surpassed the previous intraday record of US $70.85 a barrel in European electronic trading before easing back to US $70.75. That was still 35 cents higher than on Monday, when the contract settled at a record closing price of US $70.40 a barrel. In its latest monthly report, the Organization of Petroleum Exporting Countries on Tuesday revised its demand-growth forecast for 2006 to 1.42 million barrels a day, down from 1.46 million barrels per day in the previous report. The cartel estimates that global crude-oil demand will be slightly above 84.5 million barrels per day - about half a million barrels per day lower than the current Wall Street consensus.