UN inspectors will enter Iran's controversial second uranium enrichment plant on Sunday, two days after Tehran postponed its response to a UN deal on supplying the Islamic republic with nuclear fuel.
Iranian media say the UN team is expected to spend two to three days in the country as it inspects the facility being built inside a mountain near the holy city of Qom, south of the capital.
Tehran's disclosure of the new plant to the IAEA on September 21 triggered widespread global outrage, with US President Barack Obama warning Iran would face "increased pressure" if it does not come clean on its nuclear activities.
IAEA chief Mohamed ElBaradei, who announced the Qom plant inspection during a visit to Tehran on October 4, criticised Tehran for its late disclosure of the facility's existence.
"Based on the IAEA regulations, all countries should inform the IAEA on the day they begin construction" of a nuclear plant, he said. Iran informed the agency about a year after building began.
Uranium enrichment lies at the heart of Western concerns about Iran's nuclear programme. It produces fuel for civilian reactors, but in highly extended form can also make the fissile core of an atomic weapon.
Iran has been enriching uranium at a separate facility in Natanz for several years in defiance of three sets of UN sanctions.
