Iran has further boosted its capacity for uranium enrichment, according to a report from the UN's nuclear agency, BBC News said.

The International Atomic Energy Agency (IAEA) says Tehran has now installed more than 1,000 advanced centrifuges at its Natanz enrichment plant.

It comes as the IAEA says it will resume talks with Iran on 27 September - the first such negotiations since President Hassan Rouhani was elected.

The West fears Iran wants to develop nuclear weapons - a claim it denies.

The IAEA's quarterly report says there has not been much growth in the production of the most sensitive nuclear material - uranium enriched to 20%.