The row over Iran's nuclear programme came one step closer to escalating on Friday, as the country threatened to reduce its cooperation with the International Atomic Energy Agency (IAEA) in reaction to a resolution censuring the Islamic republic.
The decision adopted by the IAEA's governing board said Iran had breached UN Security Council orders to halt nuclear activities by secretly building a new nuclear enrichment plant.
It called on Iran to halt its construction and to answer open questions about alleged nuclear weapons research.
As a reaction, Tehran would limit its cooperation with IAEA inspectors to a legally mandated minimum and stop granting voluntary access to certain nuclear sites, Ambassador Ali Asghar Soltanieh said.
"This is the minimum consequence," he said, without elaborating on possible further steps. The board's action would also jeopardise international talks that his country started in October with the five permanent Security Council members Britain, China, France, Russia and the United States, plus Germany.
"The answer is no. We will not implement a word of it," Soltanieh said about the resolution.
The IAEA decision was supported by 25 of the 35 countries on the Board of Governors, diplomats said.
Only Cuba, Malaysia and Venezuela voted against it and the rest abstained or were absent. Iran is not a board member.
By initiating this first IAEA decision on Iran since 2006, the five permanent Security Council members and Germany reinforced their position that they are ready to consider new sanctions if Tehran does not come around in the nuclear stand-off.
Iran claims it was within its rights to inform the IAEA only in September, at least two years after starting construction. But IAEA chief Mohamed ElBaradei has said Tehran was obliged to give notice as soon as it decided to build the facility in Fordu, near the city of Qom.
The IAEA board said the revelation of Fordu had reduced confidence that there are no other hidden sites.
An official close to the IAEA has said the facility is too small to make fuel for nuclear power reactors, and experts have calculated that it is just the right size to make material for one nuclear weapon per year.
Iran denies it has any plans to make atomic weapons and says this facility is a backup site in case its enrichment plant in Natanz is attacked by Israel.
The six world powers also initiated the resolution because Iran has still not officially responded to a proposed nuclear fuel agreement aimed at reducing tensions and opening the path to dialogue.
US Ambassador Glyn Davies expressed his hope that "this resolution provides some impetus for Iran to take up the offer" drafted by the IAEA.
The draft foresees Iran shipping most of its low-enriched uranium out of the country, in return for nuclear fuel made in Russia and France that would power a medical reactor in Tehran.
Soltanieh Friday again called for further negotiations on the agreement.
Davies responded by saying that patience was running out. "We can't continue talks for talks' sake."