Accusing Iran of holding back information on its atomic programme, the UN nuclear  watchdog has said it has serious concerns over the alleged research into nuclear warheads by Tehran, which owes 'substantial explanation' to convince that its designs are peaceful.
Iran is also defying UN demands to suspend uranium enrichment and is producing more powerful centrifuges, the International Atomic Energy Agency said in a strongly worded report, which is bound to renew demands from the US and its western allies for tougher sanctions against Tehran.
The report is yet to be released officially, but is said to accuse Iran of not providing all information, especially relating to 'high explosives testing' relating to nuclear programme as also uranium processing and warhead design.
"The Agency is of the view that Iran may have additional information, in particular on high explosives testing and missile related activities, which Iran should share with the agency," it said.
The information sought by IAEA is based on intelligence reports provided by the United States and other western intelligence services, which Iran has rejected as 'fabricated and baseless,' asserting that the experiments had nothing to do with the nuclear programme which is for peaceful purposes.
"Substantive explanations are required from Iran to support its statements on the alleged studies and on other information with a possible military dimension," the report said.
On centrifuges for enriching uranium, the agency is said to be concerned that Tehran is producing more powerful ones as a result of the research.
It was referring to second and third generation centrifuge at Natanz which, IAEA says, should have been reported to it.
IAEA is said to be especially concerned about the reported research into nuclear warhead and wants Iran to provide it with all information.
The report was sent to the Security Council and the IAEA Board, which would discuss it at a meeting next week and may decide to refer the matter to the Council.
'There are certain parts of their nuclear programme where the military seems to have played a role,' the New York Times said, quoting an unidentified senior official close to the agency. 'We want to understand why,' he said.
Ali Asghar Soltanieh, Iran's ambassador to the atomic energy agency, said that the report vindicated Iran's nuclear activities and shows Iran's entire nuclear activities are peaceful, the semi-official Fars News Agency reported.
The report does not say how much enriched uranium the Iranians are now producing, but the Times quoted official connected to the agency as saying that since December, it was slightly less than 150 kg, or 330 pounds, about double the amount they were producing during the same period about 18 months ago.
Despite a highly critical report, analysts say that the Bush administration is unlikely to do much with elections only six months away and presumptive Republican candidate John McCain and Democratic Front runner Barack Obama disagreeing on how to handle Iran with Obama advocating talks with the Iranian leadership.
But European Union's foreign policy chief Javier Solana plans to go to Iran in the next few weeks to present a new package of rewards to Tehran in return for abandoning its nuclear enrichment programme. Foreign ministers of UK, France, Russia, China and Germany are expected to travel with him.
