Rice made her comments today on the U.S. Fox TV network. She said the behavior of Iran's ultraconservative President Mahmud Ahmadinejad has made clear that Iran cannot be trusted with technology that could give it nuclear weapons.
Asked about possible international sanctions against Iran, Rice said she is convinced Iran's nuclear program will be referred to the UN Security Council. However, she would not set a deadline for action.
Ahmadinejad, elected in June, has caused international outrage with a series of anti-Israeli remarks.
Iran also denies Western allegations it is secretly developing a nuclear-weapons program.