"As long as we are on the ground, as long as we get cooperation from all countries that have supplied technology to Iran I am confident that we will make progress," International Atomic Energy Agency (IAEA) chief ElBaradei said after meeting in Washington with US deputy secretary of state Richard Armitage.

ElBaradei's comments came as Iran's top nuclear policy-maker Hassan Rowhani said in Tokyo that Tehran is to accept an IAEA inspection unconditionally from March 27, after having said the mission that was to take place last week would be postponed until the end of April.

"The 27th has been confirmed," Rowhani told a news conference, referring to remarks on Monday by ElBaradei that Iran had agreed to let its inspectors into the country on that date.

ElBaradei, who is to meet in Washington Wednesday with US President George W. Bush, said a report he is to prepare for a June IAEA meeting in Vienna is "crucial."

The "ball is clearly in Iran's court" to provide the cooperation needed for the IAEA to absolve it of military intentions with nuclear technology, ElBaradei had said earlier in the week.

Since February 2003 the IAEA has been trying to determine whether Iran's nuclear program is peaceful, or dedicated to secretly developing nuclear weapons as the United States claims.

In Washington, US state department deputy spokesman Adam Ereli said that the time has come for Iran "to come clean fully, unequivocally and completely" on its nuclear activities.

Iran had put off inspections scheduled for last week in order to protest a tough resolution by the IAEA against Tehran for hiding sensitive parts of its nuclear program.

Elbaradei said it was "in the interests clearly of Iran and of the international community" if "I am able to report in June that we are making good progress in understanding the Iranian program."

He said Iran had "stated since last October that they have made the strategic decision to come clean, to declare everything to us."

But their failing to declare that they had designs for sophisticated P2 centrigures for making highly enriched uranium that could be weapon-grade "was a setback," ElBaradei said.

Non-proliferation analyst Jon Wolfsthal said the IAEA is looking for weapons designs in Iran since Libya had obtained such designs from an international black market.

"If Libya got them and we think North Korea got them, then everybody thinks Iran got them too," Wolfsthal said.

ElBaradei said the inspections starting March 27 were "to clarify some of issues around the P2 and going to the pilot plant (for making enriched uranium) at Natanz (in southern Iran) to make sure it is locked, it is sealed, it is not operational."

Iran had pledged in October to suspend the enrichment of uranium as a confidence-building measure with the IAEA.

ElBaradei met Tuesday with CIA director George Tenet to discuss curbing black market trafficking in nuclear technology, an IAEA spokeswoman said.

ElBaradei had said in February that the IAEA needed more intelligence help from countries like the United States.

"Sometimes information came to us that was not very timely," he said, referring to the agreement the United States and Britain reached with Libya for Tripoli to give up its weapons of mass destruction programs.

ElBaradei said the IAEA didn't know about it "until Libya announced it," in December, after months of secret talks with Washington and London.

ElBaradei is pushing in Washington a broad agenda of tightening the non-proliferation regime, including better control of nuclear material worldwide through such measures as tougher export controls by individual countries.

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