Vienna, Jan 04 (Agencies): Iran has invited Russia, China, the European Union and its allies among the Arab and developing world to tour its nuclear sites, in an apparent move to gain support ahead of a new round of talks with six world powers.

In a letter, senior Iranian envoy Ali Asghar Soltanieh suggests the weekend of January 15 and 16 for the tour and says that meetings "with high ranking officials" are envisaged.

The new round between Tehran, and the permanent UN Security Council members—the US Russia, China, Britain, France—plus Germany, is meant to explore whether there is common ground for more substantive talks on Iran's nuclear programme, viewed by the US, and its allies as a cover for secret plans to make nuclear arms.

However, the Islamic Republic insists its uranium enrichment and other programmes are meant only for peaceful purposes to generate fuel for a future network of nuclear reactors.

International worries are great because Tehran developed its enrichment programme clandestinely and because it refuses to cooperate with the UN's International Atomic Energy Agency (IAEA) probe meant to follow up on suspicions that it experimented with components of a nuclear weapons programme. Tehran denies such work.

The offer of a visit comes more than three years after six diplomats from developing nations accredited to the IAEA visited Iran's uranium ore conversion site at Isfahan. Participating diplomats then said they could not make an assessment of Iran's nuclear aims based on what they saw at that facility in central Iran.

But the new offer appeared more wide ranging, both as far as the nations or groups invited and sites to be visited.

The US, the greatest critic of Iran's nuclear strivings, was not among those invited. China and Russia have acted to dilute originally harsh sanctions measures proposed by the US, Britain and France leading to compromise penalties enacted by the council that are milder than the West had originally hoped for.

"Acts such as Iran's invitation to several countries to tour its facilities are not a substitute for Iran fulfilling its obligations to cooperate with the IAEA and will not divert attention away from the core issues regarding Iran's nuclear program," said State Department spokesman Mark Toner.

The outreach to Moscow and Beijing represented by Tehran's offer to visit appeared to be an attempt to exacerbate any differences between the Eastern and Western powers meeting the Iranians in Istanbul.

The envisaged January startup of the Bushehr power plant, a project completed with Russian help but beset by years of delays, will deliver Iran the central stated goal of its atomic work—the generation of nuclear power.

The underground uranium enrichment facility in the central city of Natanz is of much deeper international concern. The UN Security Council has imposed four sets of sanctions on Iran for its refusal to suspend enrichment.

The diplomat said the nonaligned group and the Arab League—two staunch supporters of Iran's right to what Tehran insists is its peaceful use of nuclear energy—had already accepted the invitation.

Ehab Fahzy, Egypt's ambassador to Austria and its chief delegate to the IAEA, said he was awaiting instructions from Cairo.