The UN nuclear watchdog board of governors censured Iran on Friday over mounting suspicions it may be seeking to develop atomic bombs, after the six big powers overcame divisions on how to best deal with a defiant Tehran.

But the resolution, which won overwhelming support at the 35-nation meeting of the International Atomic Energy Agency (IAEA), omitted any concrete punitive steps, reflecting Russian and Chinese opposition to cornering Iran.

It was adopted by 32 votes for and two against - Cuba and Ecuador. Indonesia abstained.

Iran showed no sign of backing down in the protracted dispute over its atomic activities, threatening to take legal action against the Vienna-based UN agency for issuing a hard-hitting report about Tehran's nuclear program.

Last week's IAEA report presented a stash of intelligence indicating that Iran has undertaken research and experiments geared to developing a nuclear weapons capability. It has stoked tensions in the Middle East and redoubled calls in Western capitals for stiffer sanctions against Tehran.

Iran says it is enriching uranium only as fuel for nuclear power plants, not atomic weapons. It has dismissed the details in the IAEA report obtained mainly from Western spy agencies as fabricated, and accusing the IAEA of a pro-Western slant.

Iran's ambassador to the Vienna-based IAEA, Ali Asghar Soltanieh, accused the agency of leaking the report early to the United States, Britain and France. Some of its contents appeared in Western media before their release on 8 November.

Iran considers the IAEA report "unprofessional, unbalanced, illegal and politicized", Soltanieh told the board meeting before the vote, the second against Iran in as many years.

"Any resolutions based on this report ... are not legally binding, thus they are not applicable."