"We hope the Iranians will return to the table ... but one thing that is very clear is the Security Council is an option," US Secretary of State Condoleezza Rice said after talks in Paris with French leaders on Friday.
"The Iranians need to get involved in negotiations and restore the confidence of the international community that they are not trying to build a nuclear weapon," she said.
The United States and European powers suspect Iran is trying to develop nuclear arms but Iran denies this, saying its programme is for peaceful purposes.
European Union foreign policy chief Javier Solana told reporters in Salamanca, Spain, he hoped for good news on the resumption of talks on the Iran issue before an International Atomic Energy Agency (IAEA) meeting next month.
"There is a willingness on the European side to return to the negotiations. In November, there is another meeting in Vienna with all the heads of the countries that form part of the board of the International [Atomic] Energy Agency," Solana said.
"I hope that before then we can have some good news on the possible ... restarting of negotiations. We will see," he added.
The IAEA's board of governors passed a resolution last month requiring that Iran be reported to the highest UN body at a later, unspecified date over fears it aims to make atom bombs.
"The Iranians need to get involved in negotiations and restore the confidence of the international community that they are not trying to build a nuclear weapon"
US secretary of state
Diplomats have said they expect France, Britain and Germany, which had been leading negotiations with Iran, to push for that at the board's next meeting on 21 November.
UN Secretary-General Kofi Annan, also at the Ibero-American summit in Salamanca, urged a return to negotiations.
"My own sense is that everyone should go back to the negotiating table. It's the best way to resolve this issue and also they must cooperate with the atomic agency," he said.
A spokesman for President Jacques Chirac said the French leader and Rice had agreed on the need for dialogue with Tehran as well as cooperation with Russia on the issue, and that the prospect of Iran having nuclear arms was unacceptable.
French Foreign Minister Philippe Douste-Blazy, standing beside Rice, said the international community must be firm with Tehran but must also continue to believe in negotiations.
"If it is still possible to negotiate, let's do it," Douste-Blazy said.