New sanctions are crucial.

"I do not think we have lost the opportunity to stop the Iranians from having a nuclear weapon, developing nuclear weapons," Gates said. "I think that the clock is ticking."

"One of the many benefits of a resolution is that it will provide a legal platform for individual nations to then take additional actions that go well beyond the resolution itself," Gates said. "And I believe a number of nations are prepared to act pretty promptly."

Also speaking to reporters, British Defense Secretary Liam Fox said that if Iran develops nuclear weapons, it could set off a nuclear arms race in the Mideast.

"After all the sacrifices that both our countries [Britain and the United States] made getting us to the end of the Cold War, limiting nuclear proliferation and having just celebrated last year 20 year since the fall of the Berlin Wall, we surely want to do more than leave the next generation a legacy of a new nuclear arms race in the world's most unstable region," Fox said.

Gates expressed hope that diplomacy and pressure will persuade Iran that nuclear weapons will not enhance, but undermine its security.