Talking with reporters in Washington after meeting French Foreign Minister Michel Barnier, Rice said, "The United States maintains significant, I want to underline significant, deterrent capability of all kinds in the Asia-Pacific region."
Her warning follows a statement Thursday by Vice Adm. Lowell Jacoby, director of the Defense Intelligence Agency, that North Korea was able to strike U.S. territory with a nuclear-tipped missile.
Also Sunday, North Korea launched a short-range missile into the Sea of Japan.
But Rice said there should be no doubt about "our ability to deter whatever the North Koreans are up to."
She suggested North Korea's missile program should be on the agenda whenever the six-party talks resume concerning Pyongyang's nuclear ambitions. The six parties are the United States, China, Japan, South Korea, Russia and North Korea.
Three earlier meetings failed to produce an agreement, while a fourth round planned for September was canceled by North Korea.