Iran's top nuclear negotiator said Thursday that Teheran was ready to open talks with the United States over Iraq, marking a major Iranian foreign policy shift. This is the first time since the 1979 Islamic Revolution that Iran is officially calling for dialogue with the United States, which it has repeatedly condemned as "the Great Satan." "To resolve Iraqi issues and help establishment of an independent and free government in Iraq, we agree to (talks with the United States)," Ali Larijani told a closed meeting of the parliament Thursday. But on Thursday, President George W. Bush, undaunted by the difficult war in Iraq, reaffirmed his strike-first policy against terrorists and enemy nations on Thursday and said Iran may pose the biggest challenge for America. In a 49-page national security report, the president said diplomacy is the US preference in halting the spread of nuclear and other heinous weapons. "If necessary, however, under long-standing principles of self defense, we do not rule out the use of force before attacks occur - even if uncertainty remains as to the time and place of the enemy's attack," Bush wrote. Titled "National Security Strategy," the report summarizes Bush's plan for protecting America and directing US relations with other nations. It is an updated version of a report Bush issued in 2002. Iran has expressed grave concerns about the prospect of more violence in Iraq, where bloody sectarian fighting and reprisal killings have broken out in recent weeks. Larijani did not address the nuclear issue, which the United States and Iran are currently in dispute over.