"We'e not part part of the negotiating efforts, we will not be part of the negotiating effort anytime soon. But it's very important that Iran return to negotiations, and so we support the EU-3 on that basis," US Under Secretary of State Nicholas Burns told reporters in the US embassy in Paris.

He said Washington has stood behind France, Germany and Britain -- the so-called EU-3 -- since mid-March in their efforts to restrict Iran's nuclear ambitions through talks.

The decision of the UN's International Atomic Energy Agency last month to warn Iran it faced being hauled before the UN Security Council if it persisted with its uranium enrichment activities in violation of an agreement with the EU-3 showed Tehran it had little support internationally, Burns said.

"It can't count on traditional allies that it might have counted on in the past. So it seems to us that the Iranians have miscalculated," he said.

"If you only have Venezuela on your side... and you don't have China, Russia, India, Brazil the United States, Europe on your side, you're rather isolated.

"So we hope the Iranians will conclude... that they don't have a lot of countries with them and that the only possible avenue ahead is negotiations. And that will be negotiations with Europe; with France and Britain and Germany."

Burns added that the subject was one of the main issues he discussed with French officials during his one-day visit to Paris.

The under secretary, who was to travel on to India and then Japan, declined to confirm that he was also meeting with Russian officials in Paris to discuss Iran, but said: "Russia has to be part of the solution to this problem. And I think Russia will be. We haven't come to the end of our talks with Russia and other countries on this."