Vienna: The UN nuclear watchdog’s governing body voted overwhelmingly on Friday to censure Iran for developing a uranium enrichment site in secret, and demanded it freeze the project immediately.

The resolution, passed by a 25-3 margin with six absentions, was the first by the 35-nation governing board in almost four years. With rare Russian and Chinese backing, it sent a message of international exasperation with Iran’s nuclear secrecy and defiance.

But it was unclear whether the measure, sponsored by six world powers, would translate into crucial Russian-Chinese support for painful sanctions that western leaders may push for if Iran does not begin to dispel fears about its nuclear ambitions soon.

Most developing nations on the International Atomic Energy Agency board, who are in a bloc that includes Iran, opposed the move, saying it would be provocative and counterproductive. Iran warned it would undermine its relations with the IAEA.

But supporters were provoked by the September revelation of a second enrichment site Iran had been building for at least two years, a subterfuge they said fanned suspicions of more secret sites that could be dedicated to making atom bombs.

The measure also signalled diminishing tolerance of Iran’s reluctance to embrace an IAEA-brokered plan to provide it with fuel for a nuclear medicine reactor if it gives up enriched uranium that could be turned into bomb material if further refined.

The draft resolution urged Iran to immediately halt construction of the Fordow enrichment plant, located in a mountain bunker, and to clarify its original purpose and confirm it has no more hidden atomic facilities or clandestine plans for any. Iran denies it wants to build nuclear weapons, saying its atomic energy programme is purely for peaceful purposes.