World powers have asked the United Nations Security Council to intervene after Iran failed to respond to incentives aimed at ending an impasse over its nuclear programme.
The decision to send the Iran dossier back to the United Nations was taken by the foreign ministers of the five permanent Security Council members - the United States, France, Britain, Russia, China - plus Germany.
It could lead to economic sanctions against Iran but does not open the door on possible military action.
"We have no choice but to return to the United Nations Security Council," French Foreign Minister Philippe Douste-Blazy said after meeting his five counterparts.
Iran was referred to the Security Council earlier this year, but work on a UN resolution was suspended in May to allow the Iranian leadership to respond to the incentives.
World power leaders hoped the package would persuade Tehran to abandon its uranium enrichment programme and wanted a clear response before this weekend's Group of Eight industrialised nations summit in Russia.
Iran has said it would only deliver its answer by August 22nd.
But the six foreign ministers in Paris said they were not prepared to let Tehran defer the issue and instead asked the 15-nation council to order Iran to suspend all nuclear enrichment activities, which can produce fuel for either power plants or weapons.