VIENNA, Sept 15: Iran has stymied a UN inquiry into whether it researched ways to make a nuclear bomb, the International Atomic Energy Agency said on Monday and Britain said it would push hard for tougher sanctions on Iran.

Iran blamed the IAEA for the impasse. Its ambassador to the United Nations said Tehran saw no “logical and legal reason” to suspend uranium enrichment, calling on the IAEA to change its approach and work in a “legal and logical manner”.

The United States called on Iran to shelve enrichment or face the possibility of more UN sanctions, adding to relatively modest punitive measures Tehran has shrugged off.

In a confidential report, the nuclear watchdog said Iran had raised the number of centrifuges enriching uranium by 500 to 3,820 since May and was testing an advanced model able to refine nuclear fuel two to three times faster, in continuing defiance of UN resolutions.

But a senior UN official familiar with IAEA findings said Iran seemed at least two years away from enriching enough uranium for an atomic weapon, if it eventually chose to do so.

“On the issue of possible military dimensions to Iran’s nuclear programme, we have arrived at a gridlock. Without Iran’s assistance and cooperation, we cannot move forward,” said a second senior UN official.Britain went further, accusing Iran of showing “contempt for the IAEA by continuing to refuse to respond” to IAEA chief Mohamed ElBaradei’s serious concerns about research with possible military nuclear dimensions.

“We will therefore push hard for further UN sanctions in the coming weeks,” a British Foreign Office statement said.

The report will be debated by the IAEA’s 35-nation board of governors at a meeting starting on Sept 22, with the possibility that Western powers might seek a resolution against Iran.

Iran had stockpiled 480kgs of low-enriched uranium so far, the report by the Vienna-based IAEA said.

It would need 1,700kgs to convert into high-enriched uranium (HEU) for fuelling an atom bomb, said UN officials.“That would be a significant quantity, one unit of HEU, and would take on the order of two years,” said one official.

AIR DEFENCE DRILL: The report coincided with an announcement by Iran that it was staging air defence exercises in half of its 30 provinces.Air defence commander Brigadier General Ahmad Mighani “emphasised that the enemies would receive a serious response for any aggression and we would surprise them and make them regretful”, the ISNA agency in Tehran reported.

The Bush administration says it wants a diplomatic solution to the nuclear standoff, but has not ruled out military action if that fails. Iran, the world’s No 4 oil exporter, says its nuclear programme is a peaceful drive to generate electricity.

FULL DISCLOSURE: In its last report in May, the IAEA said Iran appeared to be withholding information needed to explain intelligence that it had linked projects to process uranium, test high explosives and modify a missile cone in a way suitable for a nuclear warhead.ElBaradei called on Iran then for “full disclosure” -- namely, going beyond flat denials without providing access to sites, documentation or relevant officials for interviews to substantiate their stance.

The report said nothing to that end had been done by Iran, which has acknowledged some of the activity cited, but said it was for conventional military purposes only.

“Regrettably the agency has not been able to make any substantial progress on the alleged (weaponisation) studies and other associated key remaining issues which remain of serious concern,” the report said.

It said IAEA investigators had stressed to Iran that the intelligence documentation was detailed and consistent enough “that it needs to be taken seriously (by Iran), particularly in light of the fact that, as acknowledged by Iran, some of the information contained in it was factually accurate”, it said.

But, in a nod to Iranian objections, UN officials said Iran was understandably worried about divulging information it felt could compromise its security as tensions fester between Iran and the United States and Israel.

They said another obstacle was the refusal of Western powers to let the IAEA provide Iran hard copies of the intelligence for perusal. Iran has said it has seen only electronic versions that could easily have been doctored.

“We have to recognise the legitimate security concerns of Iran, especially with their situation in the world,” one official said. “We have taken note of Iran’s concern that we are touching on their sensitive military environment,” another official said.

The report said the IAEA was trying to break this deadlock by urging Iran to specify what information was wrong and what was right in its view, but Tehran had not responded so far.

Such a gesture was becoming more urgent, particularly since the IAEA had obtained information since May suggesting Iran had done tests related to high-altitude explosions typical of a nuclear payload with “the assistance of foreign expertise”.—Reuters