Kim Jong-un discusses the strike plan with North Korean officers during an urgent operation meeting at the Supreme Command in an undisclosed location on Friday. The lettering on the map (rear left) reads as " src="http://www.globaltimes.cn/Portals/0/attachment/2011/80829e38-c55b-4af6-9542-30946d56fb3d.jpeg" Strategic Forces? US Mainland Striking Plan.? Photo: AFP KCNA via KNS ?>

China's foreign ministry on Friday said the country hopes relevant parties can work together in pushing for a turnaround of the tense situation on the Korean Peninsula, after North Korean leader Kim Jong-un ordered his country's missile units to go on standby to attack the US mainland and military bases in South Korea and the Pacific.

Chinese foreign ministry spokesman Hong Lei made the remarks at a regular press briefing, calling on all relevant parties to keep calm and exercise restraint.

Kim signed off on the order at a midnight meeting of top generals and "judged the time has come to settle accounts with the US imperialists in view of the prevailing situation," Pyongyang's official Korean Central News Agency (KCNA) said.

In the event of any "reckless" US provocation, North Korean forces should "mercilessly strike the US mainland and military bases in the Pacific, including Hawaii and Guam, and those in South Korea," he was quoted by the KCNA as saying.

The order came only hours after the US military said that it flew two radar-evading B-2 Spirit bombers to stage a trial bombing raid as part of the Foal Eagle war drills being held with South Korea.

The bombers had flown more than 10,400 kilometers from their bases in Missouri before dropping inert munitions on the Jik Do Range, in South Korea, and then returned to the continental US in a single, continuous mission, the US military said.

Russian Foreign Minister Sergei Lavrov warned Friday that increased military activity near North Korea could cause tension to spiral out of control.

South Korea denied suggestions on Friday that the bomber drills contained an implicit threat of attack on the North.

"There is no entity on earth who will strike North Korea or has expressed a wish to do so," a spokesman for the South's unification ministry said.

The South's Yonhap News Agency on Friday quoted a South Korean military official as saying that a "sharp increase" in personnel and vehicle movement had been detected at the North's mid- and long-range missile sites.

"North Korea's recent successful missile and nuclear tests have definitely given it more assertiveness in confrontation with the US and South Korea. So it can't be ruled out that its leadership might miscalculate the situation and incite a conflict," Zhang Liangui, a professor at the Institute for International Strategic Studies at the Party School of the Communist Party of China Central Committee, told the Global Times on Friday.

Cui Zhiying, director of the Korean Peninsula Research Center at the Shanghai-based Tongji University, said that North Korea's threats are more about rhetoric than reality as its missiles are not believed to be able to reach the US mainland or the military bases in the Pacific, and reports show Pyongyang has not successfully miniaturized its nuclear warheads.

The North has an arsenal of Soviet-era short-range Scud missiles that can hit South Korea but its longer-range Nodong and Musudan missiles, which could in theory hit US Pacific bases, remain untested.

"Even if North Korean missiles could hit the US bases in Japan and South Korea, I don't think they would launch such attacks because this would be a self-destructive act," Cui said.