US Secretary of State Condoleezza Rice has said the UN Security Council will make a fresh attempt to persuade Iran to discuss its nuclear programme.
Iran has apparently defied UN calls to halt uranium enrichment
Speaking in Berlin, Ms Rice said the US, Russia, Germany and the EU agreed to use the UN and other means to get Iran back to the negotiating table.
Iran's foreign minister said there was still time for a negotiated solution.
It comes as the UN's nuclear watchdog is due to report on whether Iran has halted uranium enrichment activities.
Iran denies Western claims it is secretly trying to build nuclear arms.
Tehran says its nuclear programme is for purely peaceful, energy-producing purposes.
A 60-day deadline set by the UN for Iran to halt its uranium enrichment activities expired on Wednesday.
The International Atomic Energy Agency (IAEA), the UN's nuclear watchdog, is expected to report in Vienna on Thursday that Iran has failed to comply with the UN's demands, and expanded rather than halted its nuclear fuel programme.
UN Secretary General Ban Ki-moon urged Iran to co-operate.
"I am deeply concerned again that the Iranians did not meet the deadline set by the Security Council," he said ahead of the announcement.
"The Iranian government should fully comply with the Security Council as soon as possible and engage in continued negotiations with the international community so that we will be able to address and peacefully resolve this issue."
Iran could face fresh sanctions in addition to measures targeting its nuclear and missiles programmes imposed by the UN in December.
'No military action'
But Ms Rice said efforts would continue to be made to encourage Iran to stop its nuclear work and resume talks.
"We reconfirmed that we will use our available channels and the Security Council to try and achieve that goal," she said.
UK Prime Minister Tony Blair said there were no plans for military action against Iran, but that he could not predict every set of circumstances.
"There is, as far as I know, no planning going on to make an attack on Iran and people are pursuing a diplomatic and political solution," he told BBC Radio 4's Today programme.
Iranian Foreign Minister Manouchehr Mottaki said Tehran also wanted talks.
"We were against taking Iran's dossier to the Security Council from the very beginning because it was political and illegal. We are still against discussing the issue in the Security Council," he said.
"We support negotiations for solving the problem and we think that talks are the best way to get out of the impasse while each party is stressing a diplomatic and peaceful solution to the issue."