World powers met in Washington to discuss imposing more sanctions on Iran over the Islamic state's defiance of the United Nations' demands to halt uranium enrichment.
Diplomats from the five permanent members of the UN Security Council - Britain, China, France, Russia and the US - plus Germany held talks on Friday about a new resolution to pressure Iran.
China and Russia have been reluctant to place more sanctions on Iran, pointing to Tehran's recent decision to cooperate with the International Atomic Energy Agency (IAEA), the UN nuclear watchdog agency.
Iran has rejected Western suspicions that it is using a civilian nuclear-energy programme to develop atomic weapons, and has warned that it might stop working with the IAEA if more sanctions are enacted.
US Undersecretary of State Nicholas Burns, speaking on behalf of his counterparts, said in a statement that the countries had "serious and constructive" discussions about the details of a new resolution. He did not offer specifics.
The meeting in Washington coincides with a visit by French Foreign Minister Bernard Kouchner, who created a stir when he made remarks Sunday to a French radio station that were viewed as advocating military action against Iran if Tehran does not comply.
During a press conference Friday with Kouchner, Rice said that the two countries are committed to keeping diplomatic pressure on Iran to comply with the UN.
"We had an extensive discussion of the situation in Iran and the need for Iran to adhere to the just demands of the international community," Rice said.
The UN Security Council has twice placed limited international sanctions on Iran, and has insisted that Tehran suspend uranium enrichment, a process that can be used to build weapons.
The effort to put more sanctions on Iran has been energized by France, whose new president, Nicolas Sarkozy, has taken a more hard-line approach toward Iran than his predecessor.
Kouchner and the French government have since sought to clarify the remarks, but he has not ruled out the possible use of force, echoing the position of US President George W Bush.
Kouchner met with Secretary of State Condoleezza Rice ahead of the opening of the UN General Assembly next week in New York. Rice, Kouchner and their counterparts from the other four countries will meet next week in New York to discuss Iran.