As the chief of the U.N. atomic watchdog scolded Iran for delays in divulging nuclear information, the United States suggested it was considering joining Europe in offering Tehran (search) economic incentives in exchange for abandoning its nuclear fuel program.

Any such move would be a major shift in U.S. policy. During President Bush's trip to Europe last week, leaders there urged him to join them in offering such carrots on the grounds that a united front would be more effective than a continuing U.S.-Europe split over how to persuade Iran to drop its nuclear ambitions.

Bush has said that Tehran should not be rewarded, alleging past covert nuclear activities violated terms of the Nuclear Nonproliferation Treaty (search).

However, as the trip progressed, the U.S. president seemed to exhibit more flexibility, and White House spokesman Scott McClellan (search) said Monday that Bush "is thinking through some of the ideas that were discussed."

Diplomats from EU countries familiar with Bush's meetings in Brussels suggested the president appeared to undergo a change of attitude during his discussions there.

"The Americans decided to give the Europeans time to see if these negotiations would bring fruit," one told The Associated Press, demanding anonymity. "They are into another mode."

While Iran says it wants the technology only to generate power, Washington argues it wants to do so only because the process can also produce weapons-grade material for nuclear warheads.

Iran has suspended work on its enrichment program pending negotiations with France, Germany and Britain. But it has repeatedly said the freeze is short-term, despite European hopes that it will fully scrapping its plans.

Addressing the International Atomic Energy Agency's board on Iran, agency chief Mohammed ElBaradei said Tehran had to overcome a "confidence deficit" created by past cover-ups of activities that could be used to make weapons.

In a new revelation of Tehran's past covert activities, diplomats told The Associated Press on the weekend that Iran had been provided as early as 1987 with a written list by members of the nuclear black market network that contained all it needed to set up its enrichment program. They said the Iranians had handed the agency the list only recently.

Alluding to such delays in fully revealing past illicit activities, ElBaradei spoke of a "confidence deficit," saying only better cooperation on the part of Tehran will "build the necessary confidence" to dispel world concerns about Iran's nuclear aspirations.

After two years of stormy board sessions, much the past overt tension over how to deal with Iran at the Vienna-based IAEA was absent at the start of the meeting as the U.N. nuclear watchdog awaited the result of European negotiating efforts.

The board's hands are even more tied on North Korea, the other country of concern, because it quit the agency more than two years ago. Still the meeting was expected to urge the North — which claims to have nuclear weapons — to substitute new negotiations for threats.