Appearing on "FOX News Sunday," Gates said North Korea "probably will" fire the missile, prompting host Chris Wallace to ask: "And there's nothing we can do about it?"

"No," Gates answered, adding, "I would say we're not prepared to do anything about it."

Last week, Admiral Timothy Keating, commander of U.S. forces in the Pacific, said the U.S. is "fully prepared" to shoot down the missile. But Gates said such a response is unlikely.

"I think if we had an aberrant missile, one that was headed for Hawaii, that looked like it was headed for Hawaii or something like that, we might consider it," Gates said. "But I don't think we have any plans to do anything like that at this point."

North Korea has moved a missile onto a launch pad and says it will be fired by April 8. Pyonyang insists the missile is designed for carrying a communications satellite, not a nuclear warhead that the secretive nation appears bent on developing.

Gates said while he doesn't think North Korea has the capability yet to shoot off a long-range nuclear-tipped missile, "I don't know anyone at a senior level in the American government who does not believe this technology is intended as a mask for the development of an intercontinental ballistic missile."

Gates conceded that North Korea will likely get away with thumbing its nose at the international community by test-firing the missile. He also said that six-party talks aimed at curbing Pyongyang's nuclear ambitions have been largely fruitless.

"It's very troubling," Gates said. "The reality is that the six-party talks really have not made any headway anytime recently."

Gates also lamented that the missile launch planned by dictator Kim Jong-Il comes just two months after President Obama took office.

"If this is Kim Jong-Il's welcoming present to a new president, launching a missile like this and threatening to have a nuclear test, I think it says a lot about the imperviousness of this regime in North Korea to any kind of diplomatic overtures," he said.

Gates also said Japan is unlikely to shoot down a North Korean missile unless it drops debris on the island nation.

The Obama administration has signaled it wants to scale back the deployment of a missile defense system that was initiated by former President George W. Bush. The White House is also talking about dropping plans for missile defense facilities in Poland and the Czech Republic.

Gates lamented the futility of diplomatic efforts toward North Korea and Iran, another nation with nuclear ambitions. Despite the Obama administration's talk of ramping up diplomatic overtures toward Tehran, Gates was pessimistic about that strategy.

"Frankly, from my perspective, the opportunity for success is probably more in economic sanctions in both places than it is in diplomacy," Gates said. "What gets them to the table is economic sanctions."