SINGAPORE - A top Chinese military official appealed Saturday for calm over North Korea's nuclear weapons test amid fears that Pyongyang was preparing to fire a long-range missile.

Lieutenant General Ma Xiaotian told a top-level security forum here that China understands the "concerns and worries" of North Korea's neighbours and the international community over a nuclear-armed Pyongyang.

Ma, deputy chief of the general staff of the People's Liberation Army, noted that China has expressed its "firm opposition" and "grave concern" over the Stalinist North's nuclear test earlier this week.

"We are are resolutely opposed to nuclear proliferation," Ma said at the Shangri-La Dialogue, an annual security form organised by the London-based International Institute for Strategic Studies.

"Our view is that the Korean peninsula should move towards denuclearisation and we hope that all parties concerned will remain cool-headed and take measured measures to address the problem," he said.

The general's comments came amid heightened regional tensions after North Korean leader Kim Jong-Il's regime tested a nuclear bomb Monday for the second time and renounced the armistice that ended the Korean War in 1953.

North Korea fired another short-range missile on Friday and there are reports Pyongyang is preparing for a long-range missile test.

US Defence Secretary Robert Gates said at the same security forum that North Korea's nuclear moves could spark an arms race in Asia.

He also pledged that Washington "will not stand idly by as North Korea builds the capability to wreak destruction on any target in Asia -- or on us."