Iran will grant UN inspectors "managed access" to a uranium mine and a heavy water plant within three months as part of a co-operation pact reached on Monday aimed at allaying international concern about Tehran's nuclear programme.

It was signed by UN nuclear agency chief Yukiya Amano in Tehran after Iran and six world powers failed in weekend talks in Geneva to clinch a broader diplomatic deal to end a decade-old deadlock over Iran's atomic activity.

The two negotiation tracks are separate but both centre on fears that Iran may be seeking the capability to build nuclear weapons, a charge it denies. The Iran-IAEA deal may help boost hopes ahead of a new round of big power diplomacy on November 20.

The International Atomic Energy Agency (IAEA) and Iran will "strengthen their cooperation and dialogue aimed at ensuring the exclusively peaceful nature of Iran's nuclear programme," a joint statement said.

"It was agreed that Iran and the IAEA will cooperate further with respect to verification activities to be undertaken by the IAEA to resolve all present and past issues."

That seemed in part to be a reference to a stalled IAEA investigation into suspected atomic bomb research by Iran, but it gave no detail on when and how that probe may resume.

"This goodwill gesture is likely to put Iran in a better position when its negotiators meet again with their (six power) counterparts next week in Geneva," said Iran expert Ali Vaez of the International Crisis Group think tank.

Middle East specialist Shashank Joshi at the Royal United Services Institute (RUSI) in London said much would depend on implementation: "We have had numerous false starts before."

The Vienna-based IAEA, tasked with preventing the spread of nuclear weapons in the world, has long requested more information and wider access to fulfil its mandate to supervise Iran's nuclear programme to ensure there are no military links.

Iran had until now ignored such requests. But the election of a relative moderate, Hassan Rouhani, as Iranian president in June has fuelled hopes that Iran's standoff with the West over its nuclear programme can be resolved peacefully.

An annex to the agreement listed six first steps to be taken by Feb. 11, including access to the Gchine uranium mine and the heavy water production plant near the town of Arak.

Under the accord on boosting nuclear transparency, Iran would also provide information about planned new research reactors and sites for future nuclear power plants, as well as clarify earlier statements about additional uranium enrichment facilities it has said it will build.

The IAEA last visited the Arak plant - which produces heavy water for a nearby research reactor under construction - over two years ago and now monitors it via satellite images.

The Arak reactor is of deep concern for the West as it may yield plutonium, a potential bomb fuel, once it starts up. Iran says it will make isotopes for medical and agricultural use.

Gchine is located near the Gulf port of Bandar Abbas and its annual output is estimated at around 21 tonnes of uranium, which when refined can be used to fuel power plants but also to build nuclear weapons if enriched much further.

Nuclear expert Mark Hibbs of the Carnegie Endowment think-tank described Monday's agreement in principle as positive.

"The details will have to be negotiated for specific facilities and cases, and success may ultimately depend on the atmospherics of Iran's relationship with the powers," he said.

Iran says its nuclear programme is a peaceful bid to generate electricity. But its refusal to halt sensitive work has drawn tough sanctions targeting its lifeblood oil exports.

The statement with the IAEA represents "a road map that specifies bilateral steps in relation to resolving outstanding issues," the head of Iran's atomic energy organisation, Ali Akbar Salehi, said at a news conference in Tehran with Amano.

The agreement, however, made no explicit mention of the IAEA's investigation into what it calls the possible military dimensions to Iran's nuclear programme, including long-sought access to the Parchin military base where the agency suspects nuclear-related explosives tests took place a decade ago.-Reuters