The U.S. defense secretary said Thursday that North Korea continues to pose a grave threat to international peace and pledged to protect South Korea with Washington's full military might, including its nuclear weapons.

Defense Secretary Robert Gates and his South Korean counterpart, Kim Tae-young, said their two nations will never accept North Korea as a nuclear weapons state. They accused the regime of undermining global security with its nuclear defiance.

"The United States will continue to provide extended deterrence, using the full range of military capabilities, including the nuclear umbrella to ensure" South Korea's security, Gates told Kim ahead of their formal talks.

North Korea has long demanded that the U.S. withdraw its "nuclear umbrella" from South Korea, calling it an attempt to invade the country with atomic bombs and evidence that Washington is "hostile" toward it. The communist regime has argued it needs atomic weapons to cope with what it calls "U.S. nuclear threats."

Washington and Seoul have repeatedly denied having any intention to attack the North.

"In addition to the traditional military threat, North Korea's ballistic missiles and emerging nuclear weapons programs have a destabilizing effect both regionally and internationally," Gates told a joint news conference. "We will stand together."

The strong, united stance from the two top defense officials comes amid signs of possible softening by North Korea after months of tension over the regime's nuclear and missile programs.

After defying calls for restraint and carrying out nuclear and missile tests earlier this year, North Korean leader Kim Jong Il said recently that his country could rejoin international disarmament talks, depending on the status of direct talks with the U.S.

North Korea's No. 2 nuclear negotiator, Ri Gun, was on his way to the U.S. for forums in California and New York next week, and reportedly is expected to meet with the chief U.S. nuclear negotiator, Sung Kim.

The South Korean defense minister said regardless of the recent overtures, the threat from the North remains intact.

"Although on the surface there are signs of some change from North Korea, including its recent willingness to talk, in reality the unstable situation such as the nuclear program and the military-first policy remains unchanged," Kim Tae-young said. Continued...