TEHRAN, Iran - Iran took a step on Friday toward establishing an oil market denominated in euros, a plan analysts described as highly unlikely to materialize but which in theory could have serious consequences for the U.S. economy.

Iranian state-run television said the country's oil ministry granted a license for the euro-denominated market, an idea first floated back in 2004, though just who would trade on it remains unclear.

If the market were to succeed — or if Iran simply demanded payment for its oil in euros — commodities experts said it could lead central bankers around the world to convert some dollar reserves into euros, possibly causing a decline in the dollar's value.

But if one day the world's largest oil producers allowed, or worse demanded, euros for their barrels, "it would be the financial equivalent of a nuclear strike," said A.G. Edwards commodities analyst Bill O'Grady.