Vienna  - The International Atomic Energy Agency (IAEA) increased its pressure on Iran to prove it had not conducted nuclear weapons-related work, in a report published Friday that confirmed a slight decrease in the country's enrichment activities.

In his latest report, IAEA chief Mohamed ElBaradei also said Iran had partly improved its cooperation with the Vienna-based agency by allowing better monitoring at its controversial enrichment facility in Natanz, and by allowing a visit to a reactor that is under construction.

The IAEA has been trying to shed light on documents related to past Iranian studies and research projects in which military entities were involved.

"In the light of the above, the agency has repeatedly informed Iran that it does not consider that Iran has adequately addressed the substance of the issues (...)," ElBaradei concluded.

IAEA inspectors have received intelligence information they consider "generally consistent", which includes indications Iran worked on detonators and the modification of a missile which could be related to nuclear weapons.

ElBaradei's report made clear that although Iran publicly claims this intelligence documents to be false, it has acknowledged some of this work but says it was for industrial rather than military purposes.

Concerning uranium enrichment, the IAEA said some 4,600 centrifuges were operating in Natanz on August 12, 300 fewer than reported in the previous June report.

However, 3,716 additional centrifuges have been installed which Iran is planning to use for enrichment as well in the future.

While Tehran says it is enriching uranium to fuel its power plant in Busher, the UN Security Council has passed sanctions to pressure the country to halt producing material that could also be used to make nuclear weapons if processed further.

The report came as the September deadline set by the United States to pressure Iran into agreeing to nuclear talks draws close.

Along with Britain, France, Germany, Russia and China, the US has offered Iran a package of economic and political incentives in return for concessions on its nuclear programme.

The Western countries among this group are considering pushing for additional sanctions if no positive signal is forthcoming from Tehran.

German Chancellor Angela Merkel said Thursday that the international community would consider placing restrictions on the Iranian energy sector, including its fuel imports. (dpa)