UN atomic watchdog head Mohamed ElBaradei said yesterday he wanted Iran to speed up cooperation over remaining questions on its nuclear programme.
"Iran has been actively cooperating, but I sense some slowdown in the process," Mr ElBaradei told reporters in Frankfurt before flying to Iran for talks with Iranian President Mohammad Khatami and other senior officials.
"Basically, I would like to discuss with our Iranian counterparts how to get accelerated cooperation," said Mr ElBaradei, head of the Vienna-based International Atomic Energy Agency (IAEA).
The United States accuses Iran of pursuing a nuclear weapons programme, but the Islamic Republic says its nuclear ambitions are confined to generating electricity.
Iran promised Britain, France and Germany last October it would suspend uranium enrichment and accept snap atomic checks.
If enriched to a low level, uranium can be used to fuel nuclear power stations. But if enriched further, to weapons-grade, it can be deployed in warheads.
Last month, the IAEA passed a resolution deploring Iran's failure to declare potential arms-related activities. Iran initially blocked UN inspectors after the resolution but said on Sunday a new team would arrive in two weeks.
Hawks in Washington are seeking to get the UN Security Council to impose sanctions on Iran for breaching IAEA commitments.
During his talks in Tehran, Mr ElBaradei is expected to focus on Iran's omissions of key atomic technology from an October statement that included undeclared research on advanced "P2" centrifuges that can make bomb-grade uranium.
"It is in the interests of Iran to show from now until June maximum transparency, maximum accelerated cooperation," said Mr ElBaradei.
The IAEA's board of governors meets in June when it will issue a fresh report on the status of inspections in Iran.
A Western diplomat said on Friday inspectors had found traces of bomb-grade uranium in Iran at sites other than two already named - the Natanz plant and a Kalaye Electric Company workshop.
Iran has told the IAEA contaminated centrifuge components originally came from Pakistan, and the UN watchdog has asked Pakistani authorities to let it take samples to verify Tehran's position.
"I see increasing cooperation on the part of Pakistan," said Mr ElBaradei.
On Sunday, Iran said it had no nuclear sites hidden from UN inspectors.
A group of Western diplomats who follow the IAEA had said intelligence prompted suspicion Iran had not stopped enriching uranium but had moved enrichment activities to smaller sites out of view from the UN.