Dr Mohammed ElBaradei, the head of the UN's nuclear agency, said today that Iran should sign up to new treaty obligations allowing tougher inspections to make its nuclear power programme more transparent.
If Iran accepted greater transparency, then international restrictions on nuclear technology could be gradually lifted, "but to create confidence it takes time", he told reporters in an interview as he arrived in Rome for a conference.
Dr ElBaradei, head of the International Atomic Energy Agency (IAEA), is due to visit Iran on Wednesday as part of efforts to resolve a dispute over Iran's nuclear ambitions.
The United States accuses the Islamic republic of seeking atomic weapons.
The United Nations, United States, Russia and the European Union have all urged Tehran to allow more intrusive, short-notice nuclear inspections, after an IAEA report criticised Iran last month for failing to fully report its atomic activities.
Iran is a signatory to the nuclear Non-Proliferation Treaty (NPT) but has resisted calls to sign the pact's Additional Protocol, which would involve wider access for inspectors, saying international restrictions barring the transfer of nuclear technology to Tehran must first be lifted.
Dr ElBaradei said today that the process should work the other way -- restrictions could eased if Iran signed up.
"I think it's important that they have to take the first step," he said. "As I call it, take a 'peace offensive' to show they have done everything to demonstrate transparency.
"I'm confident, once they do that, then over time the ban or the sanction applied against nuclear technology will be gradually lifted. But to create confidence it takes time."