North Korea vowed Friday to push ahead with its "army first" policy and rely on nuclear weapons to defend itself from the joint forces of South Korea and the United States.

But the bellicose language of Foreign Minister Pak Ui Chun was immediately followed by the announcement that he would travel to Russia next week in an apparent bid to negotiate a peaceful end to the nuclear crisis.

The reclusive state's minister told Russia's Interfax news agency that he would pay a rare visit to Moscow on December 12-15 to discuss "bilateral relations and key international problems."

But he stressed in comments from Pyongyang that his country would respond to any pressure with force, and that it would rely on nuclear weapons for deterrence.

North Korea is "assured of the rectitude of our choice of the songun (army first) policy, and in strengthening a defence that relies on nuclear forces for deterrence," said Pak.

His comments came amid a flurry of behind-the-scenes diplomatic activity aimed at calming tensions that escalated further with the Stalinist state's November 23 shelling of a South Korean island in the Yellow Sea.

China -- which has failed to condemn the attack despite strong US pressure -- sent senior foreign affairs official Dai Bingguo to Pyongyang to meet leader Kim Jong-Il.

Chinese news reports said the two sides had reached a "consensus" on the peninsula but provided no further details.

US Deputy Secretary of State James Steinberg is also scheduled to visit Beijing next week in a bid to press the Chinese to take stronger action.

Unlike Beijing, Moscow has lost much of its influence on Pyongyang since the Soviet era.

As a consequence, it has also been far more critical of the Stalinist state, with which it does not even have a functioning rail link.

Moscow has repeatedly urged North Korea to rejoin the six-party peace process with South Korea, China, the United States, Japan and Russia, refusing to back Pyongyang's demand for direct negotiations with Washington.

And Moscow repeated that message on Friday in a sign of what is to come in the Pak-Lavrov talks.

"We need to think about creating conditions to restart talks between the six parties," Grigory Logvinov, said Russia's deputy pointman on North Korea, told Interfax.

"The atmosphere in the region is in a heated state," Logvinov said in comments released moments after Pak's threat.

"The main thing is to take steps to release the tension. All sides must avoid taking any actions that can escalate the situation," the Russian diplomat added.

North Korea's Pak said Pyongyang was always ready to negotiate.

"Even in the atmosphere of the escalated situation, we have expressed support of resuming the six-party negotiation process," he said.

Some analysts suggested that North Korea was turning to its former Communist provider as an act of desperation and because it was running out of other options.

"The visit of the North Korean minister to Moscow is a symbolic event. Russia is not the main actor in settling the Korean conflict, but no one else is able to do anything," said Fyodor Lukyanov, editor of Russia in Global Affairs.

"North Korea does not perceive Russia as part of the hostile West, nor does it fear it like China. Russian diplomacy has the chance to play a positive role, relieve tension, quell passions, so that the sides stop looking at each other through their gun sights."

Russia last played a major role in the crisis in 2001, when Kim Jong-Il famously took a train across the country from Kremlin talks with then-president Vladimir Putin.