An explosion on a pipeline transferring natural gas from Iran to Turkey halted supplies early on Friday, the semi-official Mehr news agency reported. \"The gas flow has been stopped temporarily ... An explosion has occurred inside Iran ... but it has been controlled and the pipeline is being repaired,\" the Mehr news agency said. The cause of the explosion was not immediately known. Mehr said exports to Turkey would be back to normal as soon as the pipeline was fixed. Sabotage is common on pipelines leading into Turkey from Iran and Iraq, where Kurdish separatist militants are based. Iran is Turkey\'s second biggest supplier of natural gas after Russia.