Iran's central bank announced an 8 per cent devaluation of the rial on Thursday and said it would enforce a single exchange rate as of Saturday, aiming to stamp out the black market where dollars have soared in recent weeks due to fears over new sanctions imposed by Western countries.

Governor Mahmoud Bahmani told state television the new dollar price of 12,260 rials would be in force as on Saturday, after the Iranian weekend.

 The bank's official reference rate, posted on its website on Thursday was 11,296 rials to the dollar.-Reuters