Kim Jong-un puts missile units on standby to attack US bases Kim Jong-un meets top North Korean military officials after US B-2 stealth bombers flew over the Korean peninsula. Photograph: ZUMA/Rex Features North Korea has put its missile units on standby to attack American military bases in South Korea and the Pacific, after the US flew two nuclear-capable stealth bombers over the Korean peninsula in a rare show of force. The North Korean leader, Kim Jong-un, 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." The official KCNA news agency said North Korea and the US could only settle their differences by "physical means." The North has an arsenal of Soviet-era short-range Scud missiles that can hit South Korea and have been proven, but its longer-range Nodong and Musudan missiles that could in theory hit US Pacific bases are untested. China, the North's sole major ally, repeated its calls for restraint on the Korean peninsula at a regular foreign ministry briefing on Friday and made no criticism of the US flights. "We hope that relevant parties will work together in pushing for a turnaround of the tense situation," foreign ministry spokesman Hong Lei told reporters. On Thursday, the United States flew two radar-evading B-2 Spirit bombers on practice runs over South Korea, responding to a series of North Korean threats. They flew from the United States and back in what appeared to be the first exercise of its kind, designed to show America's ability to conduct long-range, precision strikes "quickly and at will," the US military said. The news of Kim's response was unusually swift. "He finally signed the plan on technical preparations of strategic rockets of the KPA (Korean People's Army), ordering them to be on standby for fire so that they may strike any time the US mainland, its military bases in the operational theatres in the Pacific, including Hawaii and Guam, and those in South Korea," KCNA said. Photo released by KCNA news agency on 29 March shows Kim Jong Un at a meeting with top military officials in Pyongyang Photograph: ZUMA / Rex Features South Korea's Yonhap news agency reported there had been additional troop and vehicle movements at the North's mid- and long-range missile sites, indicating they may be ready to fire. "Sharply increased movements of vehicles and soldiers have been detected recently at North Korea's mid and long-range missile sites," Yonhap quoted a South Korean military source as saying. It was impossible to verify the report which did not specify a time frame, although South Korea's defence ministry said on Friday that it was watching shorter-range Scud missile sites closes as well as Nodong and Musudan missile batteries. North Korea has launched a daily barrage of threats since early this month when the United States and South Korea, allies in the 1950-53 Korean war, began routine military drills. South Korea and the US have said the drills are purely defensive in nature and that no incident has taken place in the decades they have been conducted in various forms. The US also flew B-52 bombers over South Korea earlier this week. North Korea has put its military on highest readiness to fight what it says are hostile forces conducting war drills. Its young leader has previously given "final orders" for its military to wage revolutionary war with South Korea. "The North Koreans have to understand that what they're doing is very dangerous," US defence secretary Chuck Hagel told reporters at the Pentagon on Thursday. We must make clear that these provocations by the North are taken by us very seriously and we'll respond to that. The US military said that its B-2 bombers had flown more than 6,500 miles to stage a trial bombing raid from their bases in Missouri as part of the war drills being held with South Korea. The bombers dropped inert munitions on the Jik Do Range, in South Korea, and then returned to the continental United States in a single, continuous mission, the military said. Thursday's drill was the first time B-2s flew round-trip from the mainland United States over South Korea and dropped inert munitions, a Pentagon spokeswoman said.