Hillary, Gates Say Nuclear Threat Changing Rapidly

U.S. officials are making a big push for President Barack Obama's new nuclear pact with Russia.

Secretary of State Hillary Rodham Clinton and Defense Secretary Robert Gates say the agreement signed this past week reflects the rapidly changing nature of the nuclear threat.

Clinton says there's a serious threat that nuclear materials could fall into the hands of terrorist groups such as al-Qaida.

As for Iran's nuclear ambitions, Gates says it will take a combination of economic pressure, better missile defense and cooperation with Mideast countries to rein in Tehran.

Gates and Clinton made the comments in interviews broadcast Sunday on NBC's "Meet the Press," CBS's "Face the Nation" and ABC's "This Week."