Iran oil sanctions a call 'back to negotiating table'
The EU has banned imports of Iranian crude oil and frozen assets belonging to Iran's central bank in its toughest sanctions yet against Tehran.
EU foreign policy chief Catherine Ashton said the sanctions were not intended to cause hardship for ordinary Iranians, but were "geared to an objective".
Speaking to the BBC's Persian service, she said it was up to Iran to show it was willing to work with the international community.