Iran, OPEC's second-largest producer, has stopped conducting oil transactions in U.S. dollars, a top Oil Ministry official said Wednesday, a concerted attempt to reduce reliance on Washington at a time of tension over Tehran's nuclear program and suspected involvement in Iraq. Iran has dramatically reduced dependence on the dollar over the past year in the face of increasing US pressure on its financial system and the fall in the value of the American currency. Oil is priced in US dollars on the world market, and the currency's depreciation has concerned producers because it has contributed to rising crude prices and eroded the value of their dollar reserves. "The dollar has totally been removed from Iran's oil transactions," Oil Ministry official Hojjatollah Ghanimifard told state-run television Wednesday. "We have agreed with all of our crude oil customers to do our transactions in non-dollar currencies."