SEOUL, South Korea — North Korean state media said Friday that the country’s leader, Kim Jong Un, ordered his missile units to be ready to strike the United States and South Korea, which South Korean officials said could signal either preparations for missile tests or just more blustering.
Kim’s order, which North Korea said was given during an emergency meeting early Friday, was similar to the one issued Tuesday when the North’s top military command told all its missile and artillery units to be on the ‘‘highest alert’’ and ready to strike the United States and South Korea in retaliation against their joint military exercises.
But by attributing such an order to its top leader, North Korea tried to add weight to its threat.
''We believe they are taking follow-up steps,’’ said Kim Min-seok, spokesman of the South Korean Defense Ministry, referring to increased activities of the North Korean military units. ‘‘South Korean and US intelligence authorities are closely watching whether North Korea is preparing its short-, medium- and long-range missiles, including its Scud, Rodong and Musudan.’’
He did not elaborate. But government officials and South Korean media said that there had been a surge in vehicle and troop movements at North Korean missile units in recent days as the United States and South Korea has been conducting joint military drills. The national news agency Yonhap quoted an anonymous military source as saying that North Korean vehicles had been moving to Tongchang-ri near the North’s western border with China, where its Unha-3 rocket blasted off in December.
North Korea might be preparing for an engine test ahead of a long-range rocket test, the source was quoted as saying. Scud and Rodong are the North’s mainstay short- and medium-range missiles. The Musudan, deployed around 2007 and displayed for the first time during a military parade in the North Korean capital, Pyongyang, in 2010, is a road-mobile intermediate-range ballistic missile with a range of more than 1,900 miles, according to the South Korean Defense Ministry.
In an angry reaction to the sanctions that the UN imposed after North Korea’s launching of a three-stage rocket in December and its third nuclear test last month, the North has repeatedly threatened to strike Washington, as well as the US military bases around the Pacific and in South Korea, with nuclear-armed long-range missiles.
A photo released by the North’s official Korean Central News Agency on Friday showed Kim Jong Un conferring with his top generals on what the agency called ‘‘plans to strike the mainland US’’ A military chart behind them showed what appeared to be trajectories of North Korean missiles hitting major cities in the United States.
North Korea also said its leader, Kim Jong Un, ‘‘finally signed the plan on technical preparations of strategic rockets of the KPA, ordering them to be on standby for fire so that they may strike any time the US mainland, its military bases in the operational theaters in the Pacific, including Hawaii and Guam, and those in South Korea.’’ KPA stands for the Korean People’s Army.
Kim Min-seok, the South Korean spokesman, said the North’s ‘‘unusual’’ public announcement of such plans was partly ‘‘psychological.’’ Many experts and South Korean officials doubted that North Korea has such long-range missiles, much less the know-how to make a nuclear warhead small enough to mount on such rockets.
But other analysts believed that the North’s new KN-08 missiles, which were put on public display last April, were indeed intercontinental ballistic missiles, although they and Musudan have never been test-launched before. They wondered whether North Korea might use the current tensions as an excuse to launch them.
The country is barred from launching ballistic missiles under UN sanctions. North Korea’s development of the KN-08 was one of the reasons the Pentagon cited last Friday when it announced a $1 billion plan to add more missile interceptors in Alaska to better protect the United States against a potential North Korean missile attack.
Although North Korea had traditionally issued strident threats and stirred up fears of a US invasion during previous joint US-South Korean military drills, Kim Jong Un has been far more aggressive in issuing such threats personally than his late father, Kim Jong Il, was. Unlike his father, who had expanded his power base from his youth, Kim Jong Un was catapulted into top leadership after his father’s sudden death in 2011 and must build his credentials as head of his ‘‘military-first’’ government, South Korean analysts and officials said.
Hours after Kim Jong Un’s call to arms, thousands of North Koreans turned out for a 90-minute mass rally at the main square in Pyongyang, chanting ‘‘Death to the US imperialists’’ and ‘‘Sweep away the US aggressors,’’ according to The Associated Press, which has a bureau in Pyongyang. Soldiers and students marched through downtown Pyongyang.