Iran leader dismisses US currency
Iranian President Mahmoud Ahmadinejad has suggested an end to the trading of oil in US dollars, calling the currency "a worthless piece of paper".
The call came at the end of a rare Opec summit, and was opposed by US ally Saudi Arabia.
The summit in Saudi Arabia was only Opec's third in 47 years.
a record high of $98.62 a barrel earlier this month
The dollar has weakened considerably against the euro and other currencies in the past 12 months.
However, in the communique Opec did make a reference to the debate, by committing itself to studying "ways and means of enhancing financial co-operation".
Iran's oil minister said that this would allow the formation of a committee to study the dollar's effect on oil prices and investigate the possibility of alternative trading currencies.