Vienna - International Atomic Energy Agency (IAEA) inspectors arrived in Vienna from Tehran Thursday, an agency spokesman confirmed, after visiting a new nuclear site that was disclosed too late under IAEA rules.

The quartet of experts spent four days at the new uranium enrichment plant near Fordu, 100 kilometres south of Tehran, as well as in the capital itself, to verify that the installation is not being built for military purposes.

Inspection team leader Herman Nackaerts said at Vienna airport that his team had had a good visit and that the IAEA would now analyze the data, according to the spokesman.

IAEA chief Mohamed ElBaradei is set to issue his next report on Iran in time for the organization's board meeting in late November.

According to the IAEA's rules, Tehran should have informed the agency about the new site as soon as it decided to build it, not in September, years after construction began. Iran says it has the right not to apply this rule, but the IAEA differs.

The revelation about Fordu again raised suspicions that Iran was trying to enrich uranium not to fuel civilian reactors, but for nuclear weapons.

Experts and diplomats said before the inspectors' trip that no nuclear technical equipment has likely been installed yet at Fordu.

The inspection was one of the agreed outcomes between Iran and world powers at talks in Geneva on October 1.

Iran's negotiating partners, Britain, China, France, Germany, Russia and the United States, are waiting for Tehran to deliver its answer to a proposal to process Iran's nuclear fuel abroad as a confidence-building measure.

Iranian media reported that Iranian ambassador Ali Asghar Soltanieh would deliver the answer to the IAEA Thursday, though it would likely include changes to ElBaradei's draft proposal.