Updated

Iran received an "extensive" written offer from the nuclear black market in the 1980s, the head of the U.N. atomic watchdog agency said Monday, reacting to reports that the list contained all the know-how required for weapons-related enrichment technology.

Mohamed ElBaradei (search), head of the International Atomic Energy Agency (search), was reacting to revelations by diplomats that Tehran had been approached by members of the nuclear black market network in the late 1980s with a written offer to set up the basics of the enrichment program now causing concerns about the Islamic Republic's nuclear aims.

Tehran has said it wants to use uranium enrichment for the peaceful purpose of power generation, but the practice also can be used to make weapons.

A two-year agency investigation already had established that Iran ran a clandestine nuclear program, including uranium enrichment, for nearly two decades.

Revealing details to The Associated Press on the weekend, the diplomats, requesting anonymity, said the new revelations indicated Iran had been offered full enrichment know-how earlier than previously believed. The diplomats said that, in cooperating with an IAEA investigation, Iran had turned over to the agency the initial written information from the network and had claimed to have refused offers of technology that specifically geared toward making nuclear weapons.

"They indicated that they did not take these people up on the entirety of the offer," ElBaradei said, alluding to the Iranian claim, adding, however, that the agency still had to "make sure that ... they only got what they told us they got out of this offer."

In giving the agency the written offer from the network of Pakistani scientist A. Q. Khan (search), Iran "showed us for the first time the offer they had, and that is good," ElBaradei told reporters.

However, he suggested in his opening remarks to the board meeting that Iran is providing information too late, saying that "in view of the past undeclared nature of significant aspects of Iran's nuclear program, a confidence deficit has been created."

Despite its focus on Iran and North Korea, the IAEA board meeting is unlikely to take concrete action concerning either country. The main attempt to deal with Iran has moved to another forum, with France, Germany and Britain working to have Tehran commit to scrapping uranium enrichment, while the agency has no leverage at all in the case of North Korea, which quit the IAEA two years ago.

Still, with the two nations considered the greatest nuclear threats, much of the meeting will deal with ways of defusing concerns. North Korea, which last month announced that it had nuclear weapons, will be urged to return to six-nation talks meant to defuse the threat, said diplomats accredited to the agency on the eve of Monday's opening session.

The diplomats also told The Associated Press on condition of anonymity that Iran would be the target of oblique criticism in the board's closed-door meetings, with senior agency officials citing some lack of cooperation with IAEA officials.

Among the problems to be discussed are delays by Tehran in informing the agency that it was building tunnels in the central city of Isfahan to house parts of its now-suspended uranium enrichment program, the diplomats said.

Mention also would be made of maintenance work on centrifuge parts and pipes by Iran that possibly violated the spirit of an agreement with the three European powers to totally freeze its enrichment program while negotiations were still ongoing. The Europeans hope to persuade Iran to scrap enrichment permanently.

In a potential strategy shift, the Bush administration is considering joining Europe in offering Iran economic incentives in exchange for abandoning its nuclear fuel program, the White House said Monday.

In the past, the administration had opposed any rewards for Tehran's cooperation. But President Bush is rethinking the issue after his trip last week to Europe, suggested White House spokesman Scott McClellan.

Still, there was evidence that the Americans would attempt to increase pressure on Tehran by the next board meeting in June, should the French, German and British talks fail.

A confidential U.S. position paper for the meeting called for a new written report on Iran by the June meeting. Furthermore, it urged board members meeting in June to "take further action if needed" against Iran — in effect a demand that Tehran be hauled before the U.N. Security Council if there is any indication it was defying the agency on nuclear matters.

A separate U.S. document outlined the need for a "Special Committee" to deal with nations violating the Nuclear Nonproliferation Treaty (search) — which Washington says Iran has done. Such a committee could "make recommendations to the board" to report suspect nations to the Security Council, said that document, also leaked to the AP.

On Sunday, Iran and Russia ignored U.S. objections and signed a nuclear fuel agreement that is key to bringing Tehran's first reactor online by mid-2006. Under the deal, Russia will provide nuclear fuel to Iran, then take back the spent fuel, a step meant as a safeguard to ensure it cannot be diverted into a weapons program.