US President George W. Bush declared Tuesday that his policy on Iran remained unchanged and pushed for continued international support to isolate Iran, even though his own intelligence agencies have found that Teheran ended its nuclear weapons program in 2003. The newly declassified National Intelligence Estimate report, released Monday, said Iran had halted its program in response to international scrutiny and pressure, but that the country was still attempting to enrich uranium. "I believed before the NIE that Iran was dangerous, and I believe after the NIE that Iran is dangerous," Bush told reporters at a White House press conference. "And I believe now is the time for the world to do the hard work necessary to convince the Iranians there is a better way forward." Despite concerns that the report will increase the hesitancy of many international players already reluctant to take harsh measures against Iran, Bush said "plenty of people understand that if they learn how to enrich, that knowledge can be transferred to a weapons program, if Iran so chooses." Already Bush had faced an uphill battle in getting Russia and China - and some European nations - to increase sanctions against Iran for failing to halt its uranium enrichment. Bush has also come under criticism at home and abroad for heated rhetoric against Iran - including a warning in October that Iran's activities could be leading to "World War III" - which some interpreted as paving the way for a potential military strike. Bush said Tuesday that despite the new assessment, "my opinion hasn't changed," and when asked if the military option was now off the table, replied: "The best diplomacy, effective diplomacy, is one of which all options are on the table." Bush said he and US Secretary of State Condoleezza Rice had been in touch with their counterparts around the world to "continue to rally" support for the US program, which this week saw movement toward a third UN Security Council sanctions resolution. But many people outside the White House maintain that the new intelligence information makes efforts toward further wide-ranging sanctions against Iran more difficult and the thought of military action untenable. "There's no question that this estimate makes it all but impossible to use military force against Iran now. Whatever secret desires there might remain in the office of the vice president and others to use force against Iran, they've been dealt a shattering setback," said Bruce Riedel, a former CIA officer who's now a senior fellow with the Brookings Institution's Saban Center. He said the president's image had taken a hit, while his political opponents would be emboldened. "It turns out World War III was averted four years ago. He looks a little bit foolish in that regard," he said, questioning what argument the administration could use for a military strike: "'We don't care that it stopped, we're going to bomb it anyway?' That wouldn't pass the laugh test in Washington." Indeed, Democrats seized on the intelligence report - compiled from a wide range of US intelligence agencies - to bolster their positions warning against a rush to war, and to challenge the administration's credibility, already strained after intelligence failures connected to the Iraq war. The office of Senate Majority Leader Harry Reid (D-Nevada) put out a "fact sheet" juxtaposing, among other things, Bush's statement that he learned of NIE assessment last week, with the UN watchdog's International Atomic Energy Agency findings in October that there was no "conclusive proof" of an Iranian nuclear weapons program. The US took a dim view when the IAEA report came out and questioned how constructive its role was in international efforts to keep Iran from enriching uranium. In response to the new intelligence, IAEA Chief Muhammad ElBaradei said the new assessment "should help to defuse the current crisis" over Iran's suspect nuclear program and growing fears that Washington may be gearing up for a possible conflict with the Islamic republic. The US has maintained that its efforts to strengthen sanctions are a means of avoiding such a conflict, but those initiatives might have also suffered as a result of the intelligence announcement. "In the short term, this is going to make the efforts to get a third round of sanctions at the UN more difficult," said Michael Jacobson, a sanctions expert with the Washington Institute for Near East Policy. "One of the rationales the US has used in pushing sanctions is the immediacy of the Iranian threat." If there is more time to handle Iran - as the report suggests - that could offer a way out of further sanctions for those who don't want them, such as Russia and China, and make it politically more difficult for European countries to sell the idea to their publics. The Bush administration, Jacobson said, will have to make the argument that the Iranian threat remains and that the extra time gives sanctions more opportunity to succeed. Bush on Tuesday seized on the finding in the report that international pressure had halted the weapons program, to show that US policy in this regard was working and should be intensified. "Many in the world are going to take heart in noting that it's diplomatic pressure that caused them to change their mind," Bush said. Israel has long been urging that sanctions be dramatically increased, and some observers suggested that Israel might feel more pressure to act if it saw the US and international community backing off on Iran. Michael Rubin, an Iran expert with the American Enterprise Institute, said NIE assessments have been incorrect before and that this report shouldn't change the US approach - particularly since an Iran with enriched uranium could quickly restore its weapons program - but likely will. "If US and Israel intelligence comes to different conclusions about whether Iran is continuing a nuclear weapons program," with Israel feeling the threat is more immediate, he said, "then you have a situation in which Israel might [be more inclined] to take unilateral action." He concluded, "The situation has become a lot more dangerous." Iran was clearly hopeful the unclassified summary of the NIE would undermine any consensus among the UN powers. "The US and its allies should accept nuclear rights of [the] Iranian nation. There is no other way, of course," President Mahmoud Ahmadinejad said during a meeting with the Swedish ambassador, without directly mentioning the new report, according to the presidency Web site. Foreign Minister Manouchehr Mottaki said the US would face more failure if it continued its former policy toward Iran's nuclear case. "Our advice is that they correct their mistakes regarding Iran's nuclear issue," he told state television. Mottaki's spokesman Muhammad Ali Hosseini said the new report proved that US warnings over the danger of Iran's nuclear program "are baseless and unreliable." Hosseini said the new US intelligence report meant that Washington's push to refer the case over Iran's nuclear program to the UN Security Council in 2006 for sanctions was "illegal," since it showed Iran had no weapons program at the time. AP contributed to this report.