Despite two days of talks in Tehran, no deal could be reached on granting UN inspectors access to experts, documents, and suspect sites.

Ahead of the negotiations, the International Atomic Energy Agency's chief inspector Herman Nackaerts had voiced hopes of a “structured approach” to resolving questions about Iran's nuclear ambitions.

However, no progress was made. Stumbling blocks include an Iranian demand for access to Western intelligence documents.

One western diplomat told the French news agency AFP that the Iranians had made “unacceptable” demands. Nackaerts, meanwhile, said further talks were to take place in the Iranian capital on February 12.

"Differences remain so we could not finalize the structured approach to resolve the outstanding issues regarding possible military dimensions of Iran's nuclear program," Nackaerts told reporters as he returned to Vienna.

Tehran's demand for documents

Iran denies that it is working to develop nuclear weapons, insisting that its program is for peaceful purposes only. It claims that the intelligence documents that have aroused international suspicion are fabricated.

While there are already regular inspections of declared nuclear facilities, the IAEA is keen to gain access to sites where undeclared activities are taking place.

Top of the inspectors' wish list is a visit to the Parchin military site, southeast of Tehran, where vital components of nuclear weapons were allegedly tested.

Iran's Foreign Ministry said on Tuesday that the IAEA must recognize Iran's right to develop nuclear power before gaining access to Parchin.

The IAEA came ahead of a meeting set to take place this month between Iran and the P5+1 powers - the United States, China, Russia, Britain, France and Germany. Final arrangements for that meeting have yet to be made.

rc/ipj (AFP, dpa, Reuters)