Iran's troubled currency fell to a record low against the US dollar on Saturday amid the country's increasing isolation and possible Europe Union sanctions against Tehran's Revolutionary Guards or some of its members. Ties between the EU and Tehran have deteriorated in recent months as efforts to revive nuclear talks have stalled. Iran has detained several European nationals and the bloc has become increasingly critical of the violent treatment of protesters and the use of executions. The EU is discussing a fourth round of sanctions against Iran and diplomatic sources have said members of the Revolutionary Guards will be added to the bloc's sanctions list next week. But some EU member states want to go further and classify the Guards as a whole as a terrorist organization, Reuters reported. The dollar was selling for as much as 447,000 rials on Iran's unofficial market on Saturday, compared with 430,500 the previous day, according to the foreign exchange site Bonbast.com. The rial has lost 29% of its value since nationwide protests following the death in police custody of a 22-year-old Kurdish Iranian woman, Mahsa Amini, on Sept. 16.