North Korea's official news agency has issued a warning that says if the country is attacked, it will respond with an "annihilating strike" using nuclear weapons.

The warning, published by the Korean Central News Agency, comes from an unnamed government analyst who accused the United States of increasing military pressure on the isolated Stalinist nation.

White House spokesman, Tony Snow, called the warning "deeply hypothetical" and said North Korea should return to the stalled six-party talks on its nuclear program.

North Korean vows of nuclear war follow reports that U.S. officials believe the country is preparing to test a long-range missile. U.S. and Japanese officials have warned North Korea against such a test.

Pyongyang has demanded that the United States end a financial crackdown on companies linked to North Korea before it will agree to further talks about its nuclear program. The United States has refused, saying the issues are not related.