TEHRAN - Iran showed its Natanz uranium enrichment plant to a group of United Nations nuclear watchdog ambassadors as a sign of transparency about its nuclear activities, state television reported on Sunday.

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Envoys from mainly non-aligned developing nations were on the tour. Counterparts from the West and Russia were either not invited or rejected Iran's gesture, with some saying such visits were the province of UN inspectors and could not replace talks to resolve a stand-off over Iran's nuclear work.

Natanz and the incomplete Arak heavy-water reactor are at the heart of a long-running international dispute over Iran's nuclear programme, which Tehran says has peaceful aims but the West suspects is designed to develop a weapons capability.

"The aim of this tour was to make it clear that America and some other countries are trying to distort the facts of Iran's peaceful nuclear activities," said Ali Asghar Soltanieh, Iran's ambassador to the International Atomic Energy Agency.

"This was an initiative to display the transparency of our activities ... and that the propaganda against our work is baseless," he was quoted by state television as saying.

It was not known if the envoys were given access to Natanz's underground centrifuge production hall.

Uranium hexafluoride (UF6) gas is fed into centrifuges installed at the Natanz site for enrichment of its fissile content to yield fuel for atomic power stations or, if refined to a very high degree, for nuclear warheads.

Iran denies any intention to produce weapons-grade uranium, saying it wants only fuel for a future network of power plants.

In Norway, a newspaper cited US diplomatic cables as saying that Iran has been developing contacts in more than 30 countries to acquire technology, equipment and raw materials needed to assemble a nuclear bomb.

Aftenposten said that according to the cables, obtained by WikiLeaks, more than 350 Iranian companies and organisations were involved in the pursuit of nuclear and missile technology between 2006 and 2010.

Western powers not welcome

Iran snubbed the United States, Britain, France and Germany by not inviting their IAEA ambassadors on the nuclear site tour. The envoys had toured the incomplete Arak complex on Saturday.

Western officials, including the EU, dismissed Iran's invitation as a gambit to divide six world powers trying with a mix of negotiations and sanctions to get Iran to restrain its nuclear programme and open it up to unfettered UN inspections.

The next talks will be in Istanbul on January 21-22.

Analysts said the selective invitation might have been aimed at fraying a new harmony among the US and European governments on the one hand, and Russia and China in their approach to Iran, on how to approach its nuclear activity.

Soltanieh disagreed, saying the tour aimed at easing mistrust in Iran's nuclear work. The envoys will stay in Iran until Monday. "Those countries that didn't join us in this visit have lost a great opportunity," Soltanieh said.

Expectations of a breakthrough at the Istanbul meeting are low after a first round of talks in Geneva last month failed to make substantial progress. Iran has repeatedly said it had no intention to halt enrichment, calling it a sovereign right.

"Time is on our side in the talks with the (six powers), and not on the side of the Western countries," acting Foreign Minister Ali Akbar Salehi, who is also head of Iran's Atomic Energy Organisation, told state television on Sunday.

Salehi had said on Saturday that the Islamic Republic's enrichment activities were "progressing strongly".

"The world has to acknowledge our rights finally," said Salehi, the student news agency ISNA reported.

Iran has been hit by four round of UN sanctions and the United States and the EU have imposed extra sanctions to push Iran to suspend sensitive uranium enrichment-related work in exchange for a packet of trade and diplomatic incentives.