Seoul  - South Korea can rely on the United States to defend it from its neighbour as North Korea develops its nuclear and missile capabilities, US Defence Secretary Robert Gates said Thursday on a visit to Seoul.

Both Gates and his South Korean counterpart, Kim Tae Young, criticized the nuclear and missile tests North Korea has carried out this year as "grave threats to peace and stability" for South Korea, the region and the international community.

"Secretary Gates reaffirmed the US commitment to provide extended deterrence for the ROK, using the full range of military capabilities, to include the US nuclear umbrella, conventional strike and missile capabilities," said a joint statement issued after the two ministers met for annual bilateral security talks.

The ROK refers to the Republic of Korea, the official name of South Korea, where the United States has 28,500 soldiers stationed.

Gates said at a press conference with Kim that North Korea's nuclear weapons programme has a destabilizing effect regionally and internationally.

"We will stand together with South Korea and our other allies and partners toward achieving the complete, verifiable denuclearization of North Korea," he said.

A day earlier, Gates had warned South Korean and US soldiers that the danger posed by North Korea has grown as it develops its nuclear and missile programmes and engages in proliferation.

North Korea in April pulled out of six-nation talks aimed at ending its nuclear weapons programme, in which the United States and South Korea are involved as well as China, Japan and Russia. Then in May, North Korea carried out its second nuclear test, which was internationally condemned.

Pyongyang recently indicated it was willing to return to the six-nation negotiations if Washington would engage in direct talks with it.

However, Gates and Kim said Thursday that neither of their countries would accept North Korea's return to the negotiating table as a nuclear weapons state.

Their assertion came a day after US Secretary of State Hillary Rodham Clinton vowed that the United States would never establish normalized relations with North Korea as long as the Stalinist state has nuclear weapons.

"Current sanctions will not be relaxed until Pyongyang takes verifiable, irreversible steps toward complete denuclearization," Clinton said in Washington. "Its leaders should be under no illusion that the United States will ever have normal, sanctions-free relations with a nuclear-armed North Korea." (dpa)