The head of the UN atomic watchdog was due to hold talks today with senior Iranian officials on allowing its inspectors into Iran's new uranium enrichment plant at the holy city of Qom, local media said.
Mohamed ElBaradei's visit comes after Washington and its allies demanded rapid progress in revived talks in Geneva last week on Iran's controversial nuclear programme.
The International Atomic Energy Agency (IAEA) chief was expected to meet Ali Akbar Salehi, the head of the Iranian Atomic Energy Organisation, and other officials on Sunday, news agencies said.
The main purpose of his visit is to discuss with Iranian officials "how UN inspectors can visit the Qom plant, other nuclear facilities and to discuss more cooperation," the ILNA news agency said.
Iran's English-language Press TV said ElBaradei would not visit the Qom facility himself during his trip.
The disclosure prior to the Geneva talks by Iran that it is building a second nuclear enrichment plant inside a mountain at Qom triggered worldwide outrage.
His visit comes amid mounting international pressure against Iran over its uranium enrichment programme, including a demand by US President Barack Obama after Thursday's talks in Geneva for swift and "constructive" action by Tehran.
Obama said that the Geneva meeting, which included the highest-level direct talks between the United States and Iran in three decades, marked a "constructive" start to defusing the nuclear standoff.