SEOUL, April 4 (Yonhap) -- North Korea has recently moved an intermediate-range missile to its east coast in a display of military power or a preparatory move for an imminent liftoff, multiple sources in Seoul said Thursday.
The North's apparent missile relocation has prompted the United States to move its advanced missile defense system to its base on the Pacific Ocean island of Guam along with radar systems.
It has yet to be confirmed whether the missile was carrying a warhead, but the sources forecast that Pyongyang is likely to fire it off around the middle of April, when North Koreans celebrate the birthday of the North's founder Kim Il-sung.
The latest military move comes as the North has been ratcheting up its war threats against South Korea and the U.S. in recent weeks, with the communist country reportedly authorizing its army to strike the U.S. earlier in the day.
"South Korean and U.S. intelligence officials spotted the North moving an object that appears to be an intermediate-range missile to its east coast," a military source said, asking for anonymity citing classified military information. "According to intelligence analysis, it is thought to be a 'Musudan' missile."
The North has not yet conducted a test firing of the Musudan missile, which is estimated to have a 3,000-4,000 kilometer range, putting the U.S. base in Guam within striking distance.
The North deployed about 50 missiles in 2009 and revealed them to the international community in October 2010 during a military parade in Pyongyang, officials said, noting it was not clear whether the recently-moved missile was fitted with a warhead.
"We are closely looking into North Korea's intentions and whether it was aimed at demonstrating a show of force or threatening the U.S.," the source said.
Outside watchers see a high chance that Pyongyang may launch the missile in mid-April to celebrate the April 15 birthday of Kim Il-sung, the communist nation's late founder and the young leader Kim Jong-un's grandfather, in a move to bolster the regime's grip on power.
The North is known to have declared a "no-fly, no-sail zone" along the lower portion of its east coast until the end of April, official said, when the two-month joint drills by South Korean and the U.S. forces end.
Despite the warlike rhetoric in recent months, there is no indication that a North Korean provocation is imminent, though firearms training and infiltration drills using submarines and air cushioned vessels are currently under way, a senior military official said.
Meanwhile, Japan's Asahi Shimbun on Thursday reported that the North has moved KN-08, a long-range missile that is believed to have a range of 10,000 km, to its east coast, citing government sources in Seoul, Tokyo and Washington.
In the wake of Pyongyang's threats to strike the U.S. in recent weeks, the Pentagon on Wednesday announced its plan to deploy a Terminal High Altitude Area Defense System (THAAD), an advanced ballistic missile defense system, to Guam in the coming weeks as a "precautionary move" to bolster its defense posture.
The latest move comes after the U.S. Navy earlier this week moved a Sea-Based X-Band Radar (SBX-1) based in Hawaii to the Western Pacific Ocean to better monitor potential attempts from North Korea to launch a long-range missile.
In response the U.S. move, the North Korean army said Thursday it had final approval to launch "merciless" military strikes on the U.S.
In a statement published by the official Korean Central News Agency, the General Staff of the Korean People's Army said it was formally informing Washington that reckless U.S. threats would be hit by "cutting-edge smaller, lighter and diversified nuclear strike means."
North Korea had threatened a "pre-emptive" nuclear strike against the U.S. a month ago, and last week the supreme army command ordered its strategic rocket units to combat ready status for strikes on the U.S. mainland and U.S. bases in Guam and Hawaii.