The UN nuclear watchdog chief has begun talks with Iran’s top officials in Tehran over the country’s controversial nuclear programme.
Yukiya Amano, the head of the International Atomic Energy Agency, met the head of Iran's nuclear energy organisation, Fereydoun Abbasi-Davani, hours after his pre-dawn arrival on Monday, according to ISNA news agency.
Amano is also expected to meet Iran's chief nuclear negotiator Saeed Jalili and Foreign Minister Ali Akbar Salehi, ahead of a crunch meeting in Baghdad on Wednesday between Iran and a group of world powers to discuss concerns over its suspected nuclear weapons drive.
Al Jazeera's Imran Khan, reporting from Tehran, said Amano's visit is "crucial".
"Many people say that a man of this stature wouldn't visit [Iran] at this crucial time unless they were very close to singing a framework deal [to inspect suspected weapons sites]," our correspondent said.
Khan said this trip represents the potential end of a stalemate, as the last IAEA chief to visit Iran was Mohamed ElBaradei in 2009.
|Click on the image above for an interactive map of Iran's
nuclear sites, including Parchin [Al Jazeera/Ben Piven]
By promising co-operation with UN inspectors, diplomats say Iran might aim for leverage ahead of the broader negotiations, where the US and its allies want Iran to halt works they say are cover for developing nuclear weapons.
Western sanctions on Iran's energy exports, and threats by Israel and Washington of military action, have pushed up world oil prices.
Details on Amano's hurried mission were scarce.
"We regard the visit by the agency's director general as a gesture of goodwill," Ali Akbar Salehi, the Iranian foreign minister, was quoted as saying by the Iranian student news agency on Saturday.
He hoped for agreement on a "new modality" to work with the UN agency that would "help clear up the ambiguities".
The nuclear watchdog wants access to sites, officials and documents to shed light on activities in Iran that could be used
to develop the capability to make nuclear weapons, especially the Parchin military complex southeast of Tehran.
Two meetings between Iran and senior Amano aides in Tehran in January and February failed to make any notable progress.
Heading off crisis
Such a deal would also not be enough in itself to allay international concerns. World powers want Iran to curb uranium
enrichment, which can have both civilian and military purposes.
Iran insists its nuclear programme is intended only to generate electricity and other civilian uses.
Unlike Israel, assumed to have the Middle East's only nuclear arsenal, Iran is a signatory to treaties that oblige it to work with the IAEA.
Leaders of the G8, worried about the effect of high oil prices on their faltering economies, raised the pressure on Iran on Saturday, signalling their readiness to tap into emergency oil stockpiles this summer if tougher new sanctions on Tehran threaten to strain supplies.
|In-depth coverage of a growing regional debate|
"All of us are firmly committed to continuing with the approach of sanctions and pressure in combination with diplomatic discussions," US President Barack Obama said.
Israel, convinced a nuclear-armed Iran would pose a mortal threat, has, like the US, not ruled out air strikes
to stop Iran's atomic progress if it deems diplomacy has failed.
In Baghdad, the powers' main goal is to get Iran to stop the higher-grade uranium enrichment it started two years ago and has since expanded, shortening the time needed for any weapons bid.
Iran says it needs the uranium enriched to a fissile concentration of 20 per cent for its medical research reactor.
An adviser to Iran's Supreme Leader Ayatollah Ali Khamenei said there were hopes the Baghdad meeting would be successful.
The IAEA wants Iran to address issues raised by an agency report last year that revealed intelligence pointing to past and possibly ongoing activity to help develop atomic arms.
Iran says the intelligence is fabricated, and has so far resisted requests for inspectors to visit Parchin.