Condoleezza Rice told reporters on Thursday that there will "have to be some consequence" for Iran's refusal to suspend uranium enrichment activities, as the Security Council president demanded in a statement two weeks ago.
Rice spoke to reporters after a meeting with Canadian Foreign Minister Peter MacKay.
"There is no doubt that Iran continues to defy the will of the international community despite the fact that the international community very clearly said stop," Rice said.
One option, she said, is the ability to compel Iran through provisions under Chapter 7 of the UN Charter. These provisions permit measures to ensure that the will of the international system is carried out.
Earlier on Thursday, several top US intelligence officials said Iran was years from obtaining the materials and technology necessary for a nuclear weapon despite its announcement this week that it had begun enriching uranium.
Kenneth Brill, the head of the new National Counterproliferation Centre, said the Iranian government had blustered before about developments that did not readily materialise.
"We really have to see what's happened in Iran," Brill said. "There is still a very significant amount of time that needs to be worked through by the Iranians to get to where they want to go."
Defending the quality of intelligence assessments, Brill said much of what the intelligence agencies had predicted had been validated by the IAEA and others.
Tehran insists its work is only for peaceful, civilian purposes, but the US and a number of its allies think it is after a nuclear arsenal.
China on Friday said dialogue was the key to resolving the West's nuclear stand-off with Iran.
Vice Foreign Minister Yang Jiechi, briefing reporters on President Hu Jintao's visit to the United States next week, was asked whether Iran and North Korea would be raised.
Yang said all international issues of common concern would be discussed.
"We hope all parties will adopt a cool-headed approach," he told a news conference when asked about Iran. "Dialogue is better than confrontation. We should work together toward this end."
Mohamed ElBaradei, head of the International Atomic Energy Agency, said on Thursday that Iran had told him it would step up efforts to answer questions on its nuclear plans.
ElBaradei is due to report to the UN Security Council at the end of April.