Bush Tells Iran to Disclose Nuclear Activities

McConnell told Bush that it would take time to validate the new information, but officials said they saw no need to adjust the administration's rhetoric.

In his brief comments, Bush chose to emphasize the part of Monday's National Intelligence Estimate that asserted Iran had a covert nuclear program until 2003. Bush said it is "clear from the latest NIE that the Iranian government has more to explain about its nuclear intentions and past actions, especially the covert nuclear weapons program pursued until the fall of 2003."

Bush said he felt reassured by the conversations his top national security advisers have had recently with counterparts from France, Britain, Russia and Germany. "These countries understand that the Iranian nuclear issue is a problem, and continues to be a problem that must be addressed by the international community," he said.

Leading Democrats, including House Speaker Nancy Pelosi (Calif.) and Senate Majority Leader Harry M. Reid (Nev.), have called on Bush to try more aggressive diplomacy on Iran, and even some allies said the administration should drop its insistence that Iran suspend nuclear enrichment.

Sen. Joseph R. Biden Jr. (D-Del.), chairman of the Foreign Relations Committee and a presidential candidate, said if Bush believes nothing has changed because of the intelligence report, he is in denial.

"If we don't use this moment to end this administration's fixation on regime change and bring the world onboard to a new approach of conduct change, with coordinated pressure and real incentives, the result will be to isolate the United States, not Iran," Biden said.

Outside experts said the White House is struggling to keep its policy on Iran from imploding.

"The American juggernaut, which was having considerable success in lining up the international community behind tougher sanctions and isolating Iran, has been forced to a screeching halt. So now they're trying to get it moving again," said Martin Indyk, who was assistant secretary of state for Near East affairs under President Bill Clinton and now head of the Brookings Institution's Saban Center.

But Gary Schmitt, director of advanced strategic studies at the American Enterprise Institute, which is often supportive of the president on foreign policy, said the new intelligence estimate can be read as supporting the administration's position. "If they don't stick to their position, their credibility with diplomatic allies in Europe and the Gulf who are out on a limb . . . will be shot," Schmitt said in an e-mail exchange.

In Iran, meanwhile, President Mahmoud Ahmadinejad called the new report "a declaration of victory for the Iranian nation" in the diplomatic showdown with world powers over its nuclear issue. In Brazil, Mohamed ElBaradei, head of the U.N. nuclear watchdog agency, said the NIE "somewhat vindicated" Iran, which has emphatically denied it intends to develop a bomb.

U.S. officials dismissed Iran's triumphal rhetoric. Asked about the Iranian president's assertion, Bush grinned broadly and said, "You can mark down I chuckled."

Wright reported from Washington.