"That was our policy ? and that's our policy going forward," said Stephen Hadley, the president's national security adviser. "We have the right strategy."

Iran ceased its secret nuclear weapons program in 2003 and has not resumed work toward building nuclear arms, a National Intelligence Estimate released Monday says. The estimate reverses claims the intelligence community made two years ago that Iran appeared "determined to develop" a nuclear weapons program.

The new estimate did not explain why the intelligence community did not know Iran had stopped its weapons program before the 2005 estimate was released.

The estimate, reflecting the collective judgment of the nation's 16 intelligence agencies, also concludes that Tehran probably is "keeping open the option to develop nuclear weapons" by continuing to build missiles and pursue a civilian nuclear power program.

Iran, intelligence analysts concluded, halted weapons development in response to international scrutiny and the threat of increased sanctions.

U.S. officials are still trying to enlist more nations to bring sanctions against Iran. On Monday, Undersecretary of State Nicholas Burns said he met with Chinese officials to agree on key issues involved in imposing a third set of United Nations sanctions on Iran for continuing a nuclear weapons program.

Shortly after Burns' comments in Singapore, the intelligence community released its estimate saying Iran had stopped its nuclear weapons program in 2003.

Despite the differences from the 2005 analysis, intelligence officials thought it was important to set the record straight by making public that "our understanding of Iran's capabilities have changed," said Donald Kerr, deputy director of national intelligence.

Monday's estimate was a double "good news story," said Sen. Kit Bond of Missouri, the ranking Republican on the Senate Intelligence Committee.

"The intelligence community was willing to reconsider an important intelligence judgment," Bond said. "Iran doesn't appear to be currently working on a bomb."

Sen. Joseph Biden, D-Del., who chairs the Senate Foreign Relations Committee, said the estimate undercuts the administration's "obsession with regime change and irresponsible talk of World War III." Last month, President Bush said the U.S. policy toward Iran was aimed at avoiding "World War III."

"The NIE makes clear that the right combination of pressure and positive incentives could prompt Tehran to extend the current halt to its nuclear weapons program," said Biden, a Democratic candidate for president.

Mordechai Kedar, who served in Israel's military intelligence for 25 years and is a researcher at the Begin-Sadat Center for Strategic Studies in Tel Aviv, said Israel's intelligence community disagrees with the latest estimate.

"This is a matter of interpretation of data. I do believe that the U.S. and Israel share the same data, but the dispute is about interpreting the data. ? Only a blind man cannot see their efforts to put a hand on a nuclear weapon. They are threatening the world."

Contributing: Charles Levinson