VIENNA, Nov 18: The UN nuclear watchdog said in a confidential report on Friday that Iran had given it a document that included partial instructions for making the core of a nuclear bomb.

The Iranians told the IAEA the document had come to them unsolicited from people linked to Pakistani scientist Dr Abdul Qadeer Khan, according to diplomats.

The US ambassador to the International Atomic Energy Agency (IAEA) said the disclosure raised concerns about weaponization, but other diplomats and an American nuclear expert were more cautious, saying more investigation was needed into the issue.

“Iran’s full transparency is indispensable and overdue,” said IAEA chief Mohamed ElBaradei in a confidential report to the agency’s board of governors.

The report said that among other documents it had found one ‘on the casting and machining of enriched, natural and depleted uranium into hemispherical forms’.

One European diplomat described it as a ‘cookbook’ for the enriched uranium core of a nuclear weapon.

But the nuclear expert, David Albright of the Institute for Science and International security, said it was far from a step-by-step guide to producing a bomb core.

“Iran has gone from saying it got nothing on this subject to (saying it got) a little bit,” he said. “But the question remains: did Iran get more than it admitted to?”

Iran says it wants to use nuclear power only to generate electricity and has the legal right to do so.

While Iran had been ‘more forthcoming’ in providing access to documents and information in some areas, questions on the peaceful nature of its nuclear plans remained, the report said.

The IAEA board meets on Thursday to decide whether to send Iran to the Security Council for failing to allay suspicions it is hiding a nuclear arms programme behind a civilian one.

“This (document) opens new concerns about weaponization that Iran has failed to address,” the US ambassador to the IAEA, Gregory Schulte, said in a statement.

Britain said the IAEA should investigate the questions raised in its latest report.

The IAEA report asked Iran to provide information on dual-use equipment and allow visits to sites such as those at Lavizan. Washington says one site was used for sensitive nuclear Work, but was bulldozed before IAEA inspectors could visit it.

Iran’s chief nuclear negotiator Ali Larijani said earlier the IAEA should justify its request for access to Lavizan.

“We cannot accept this demand just because they wish it, especially since Lavizan-Shian is a military complex,” the semi-official ISNA students’ news agency quoted him as saying. —Reuters