London, Feb 3 (DPA) Iran could develop a nuclear weapon within two years, but the time span could be shorter if untested uranium enrichment methods were used, a report published by the London-based International Institute for Strategic Studies (IISS) said Thursday.

‘The totality of the evidence indicates beyond reasonable doubt that Iran also seeks a capability to produce nuclear weapons should its leaders choose to take this momentous step,’ said the strategic dossier on Iran’s Nuclear, Chemical and Biological Capabilities.

Under the most likely scenario worked out by experts, it would take Tehran over two years to make a single atomic bomb, said the IISS.

However, one of the scenarios mapped out in its assessment showed that Iranian scientists would be able to produce enough weapons-grade enriched uranium for a weapon in just four weeks.

Iran’s current stocks of low-enriched uranium would be enough for one or two nuclear weapons if further enriched, the IISS study found.

If Tehran used the production method developed by Pakistan – which is sold on the black market to Iran, North Korea and Libya by disgraced Pakistani nuclear scientist A.Q. Khan – it would take just over a year and seven months to make the first bomb.

However, it would take at least 32 weeks to produce enough highly-enriched uranium for each subsequent bomb. Employing an unproven technique known as a ‘batch enrichment process’ would reduce the time needed to six months for the material for the first weapon and four months for further bombs.

‘The minimum timeline, then, for the first weapon, is over two years under the Pakistan method and one year for the batch method. Developing a means to deliver a nuclear weapon adds to the timeline,’ the IISS report concluded.

The study noted that one bomb would not be enough for a ‘credible nuclear deterrent’ and that producing an arsenal of weapons would take more time.

Lead author Mark Fitzpatrick, director of the non-proliferation and disarmament programme of the IISS, said it was ‘scary’ to imagine what would happen if Iran would be capable of using ‘third generation’ centrifuges to enrich uranium for a weapons programme.

‘That’s the scary part,’ he said in a question-and-answer session after the launch.

‘If Iran were able to get the third generation working well and producing in large numbers, the time to produce a weapon’s worth of HEU (highly-enriched uranium) reduces to four weeks,’ he said.

‘If they had a clandestine plant with almost 6,000 centrifuges operating – the number that were in the A.Q. Khan design that they sold to Libya – if they had 6,000 of these working and they were this most advanced third generation, four weeks.’

However, Fitzpatrick stressed that this was only a theoretical scenario.

The IISS also concluded that claims about Iran’s supposed chemical and biological weapons programmes could not be confirmed from publicly-available information and ‘may have been exaggerated’.

Iran’s capability to produce nuclear weapons had been ‘growing inexorably for the 25 years’, but it had not been an ‘all-out, crash effort’, said the report.

However, many estimates compiled by Western intelligence agencies had failed ‘to clearly distinguish between the time needed to produce the fissile material for a weapon, or the difference between a nuclear device and a deliverable weapon,’ said Fitzpatrick.

‘Iran hopes to maintain ambiguity over its intentions. If it does decide to build nuclear weapons, this would likely be detected before it assembled a single weapon, much less the small arsenal that would be needed to make the risk worthwhile. An Iranian nuclear weapon is therefore not inevitable,’ said the IISS report.