US Secretary of State Condoleezza Rice said Thursday the credibility of the United Nations Security Council was as stake, as the world body decides how to deal with Iran's likely rejection of Friday's UN deadline to bring its nuclear program in line with international demands. "In order to be credible, the Security Council of course has to act," Rice told reporters at a NATO foreign ministers' meeting. She said it was "pretty clear" that Iran would not meet the requirements set by the UN nuclear watchdog, the International Atomic Energy Agency, regarding the enrichment of uranium - a process that can produce fuel for generators or fissile material for nuclear bombs. "I think it goes without saying that the United States believes ... that in order to be credible the Security Council of course has to act," she said. "The Security Council is the primary and most important institution for the maintenance of peace and stability and security, and it cannot have its will and its word simply ignored by a member state."