TEHERAN (AFP) - Iran and the UN nuclear watchdog on Monday reached agreement on a "roadmap for cooperation" to resolve remaining issues linked to Iran's controversial atomic drive, nuclear chief Ali Akbar Salehi said.

"The joint statement that was signed today details a roadmap for cooperation that determines mutual steps to resolve remaining issues," Mr Salehi said at a joint news conference in Tehran with International Atomic Energy Agency (IAEA) head Yukiya Amano.

Mr Amano hailed the deal as "an important step" but added "much more must be done".

The IAEA conducts regular inspections of Iran's nuclear facilities but it also wants to investigate allegations that Iran conducted nuclear weapons research before 2003 and possibly since then.

Mr Salehi said the deal signed with the IAEA includes a "six-step annex" and that in a show of goodwill, Tehran had agreed to allow IAEA inspectors to visit the heavy water production plant in Arak as well as the Gachin uranium mine in the south.

The Arak heavy-water reactor in central Iran, which could be operational by the end of next year, is a major source of concern for Western powers.

Its official function is to produce plutonium for medical research but it could potentially be used for military purposes.

The issue of Arak is said to have contributed to failure in reaching an agreement in parallel diplomatic efforts between Iran and world powers over Tehran's nuclear drive.

Iran denies seeking or ever having sought nuclear weapons, and says the claims are based on faulty intelligence from agencies such as CIA and Israel's Mossad.

Mr Salehi and Mr Amano did not mention the Parchin military base south-east of Tehran as being part of the deal struck on Monday.

The IAEA in particular wants to visit Parchin where intelligence evidence suggests Iran may have carried out weaponisation research.

Iran denies seeking or ever having sought nuclear weapons, and says the claims are based on faulty intelligence from agencies such as CIA and Israel's Mossad.

Full details of Monday's agreement are yet to be published.