Iran allowed UN inspectors to revisit a heavy-water reactor site yesterday, a place off-limits since April, in a show of transparency meant to help ward off harsher UN sanctions over its disputed nuclear activity. Iran agreed to grant International Atomic Energy Agency inspectors fresh access to the Arak complex under construction as part of an "action plan" to defuse suspicions of a covert atom bomb project, as demanded by the UN Security Council.

Tehran has refused the Council's main demand that it suspend all efforts to produce nuclear fuel - defiance that has saddled the Islamic Republic with two sets of modest sanctions.

But diplomats say Iran hopes to pre-empt more punishing sanctions by answering IAEA questions about its activity and improve IAEA access to sensitive sites. Iran's initiative led big powers to put off more sanctions at least until September. Tehran barred inspectors from Arak four months ago to protest at a second round of sanctions, insisting its programme - centred on its Natanz uranium enrichment plant - is solely to yield electricity, not explosives.

PHOTO CAPTION

A general view of a heavy water plant in Arak in 2006. (AFP)