A US State Department official said the Iranians have had held off on their threat to resume nuclear fuel cycle activities, but the Europeans say the situation is more troubling.
The US and its allies fear Iran nuclear program could be lead to efforts to develop a nuclear bomb.
Iran’s ultimatum that it would restart its nuclear facilities put it on a collision course with Britain, France and Germany.
The European countries were trying to lure Iran away from nuclear weapons ambitions with economic and security incentives.
They have said any resumption of fuel work would scuttle an agreement struck last year in Paris.
But the US official said: “I think there is a general sense that, at least for now, the Iranians have moved away from any immediate action that would break the Paris accord.”
Iran announced on Monday that it was ready to resume the sensitive process of uranium ore conversion that had been suspended for nine months, and was gearing to remove the seals from a plant in the city of Isfahan.
But it later said it was waiting for inspectors from the International Atomic Energy Agency (IAEA), the UN watchdog, to put surveillance cameras and other controls in place.
The US official took this as providing new leeway for diplomacy.
“I think it’s extremely positive that the Iranians stepped back from breaking the seals,” he said.
His assessment contrasted with the more dire view from European officials such as French Foreign Minister Philippe Douste-Blazy who said the parties might be heading towards “a major international crisis.”
Both the United States and European Union reiterated on Tuesday that a breakdown of negotiations would likely prompt them to refer Iran to the UN Security Council for possible sanctions.
The Europeans were reportedly readying a new offer for Tehran including guaranteed fuel for a nuclear power plant the Iranians are building at Bushehr and others they may construct down the road.