Military tension reached a new high on the Korean Peninsula Thursday as North Korea was seen moving an intermediate-range missile to its east coast and the U.S. unveiled its plan to deploy a key missile defense asset to Guam.

Berating Washington for its recent deployment of strategic military assets such as the B-2 and F-22 stealth warplanes, Pyongyang’s military said it officially informed the White House and Pentagon that it had “final approval for merciless operations” against the U.S.

Seoul officials said the North’s missile in question appeared to be the Musudan ballistic missile with a range of 3,000-4,000 km. The missile brings Guam, a key U.S. strategic base in the Asia-Pacific region, within striking range.

“It is unclear whether the missile carries a warhead or not. We are closely watching it to ascertain whether the North moved it to actually fire it or in a show of force to threaten the U.S.,” a military source said, declining to be named.

Observers believe Pyongyang could launch it around the “Day of the Sun,” the birthday of its late founding father Kim Il-sung on April 15. Some 50 Musudan missiles were deployed as of 2009. The missile, which has yet to be openly tested, was first unveiled during a military parade in October 2010.

Citing Tokyo government sources, Japan’s Asahi Shimbun reported on the day that the North was seen moving what appeared to be the KN-08 missile, which experts speculate is a new intercontinental ballistic missile.

Amid escalating military threats by the North, Seoul’s Defense Minister Kim Kwan-jin said during a parliamentary session that the possibility of an all-out war on the peninsula is low. But he said that Seoul was closely watching the possibility of provocations in various forms including cyber attacks.

As Pyongyang has hardened its bellicose rhetoric against Washington, the Pentagon plans to deploy a land-based “terminal high-altitude area defense system” to Guam in the coming weeks as a precautionary move to counter a possible attack.

The deployment plan came after the Pentagon unveiled its plan last month to strengthen missile defense against the North by installing 14 additional ground-based interceptors at its bases in Alaska and California by September 2017.

“The U.S. continues to urge the North Korean leadership to cease provocative threats and choose the path of peace by complying with its international obligations,” the Pentagon said while announcing the deployment plan in a statement.

“The U.S. remains vigilant in the face of North Korean provocations and stands ready to defend U.S. territory, our allies, and our national interests.”

The THAAD system, which is part of the U.S.-led broader missile defense program, includes a truck-mounted launcher, a complement of interceptor missiles, an AN/TPY-2 tracking radar, and an integrated fire control system.

The global U.S. missile shield aims to intercept intercontinental ballistic missiles heading toward its mainland with multiple assets ― suited for different altitudes ― such as the THAAD, ship-based Standard Missile 3 and Patriot Advanced Capability-3.

During a speech at the National Defense University on Wednesday, U.S. Defense Secretary Chuck Hagel said North Korea’s bellicose rhetoric posed a “real, clear danger and threat to the U.S. and its Asia-Pacific allies,”

Pyongyang has ratcheted up its rhetoric as Seoul and Washington have moved to strengthen their allied defense posture by adopting a counter-provocation plan and display their might through high-tech weapons systems.

In an angry response to the allies’ moves, the North has threatened to strike U.S. bases in South Korea, Japan, Guam, Hawaii and its mainland.

In its latest hostile statement, the General Staff of the North Korean People’s Army warned that reckless U.S. threats would be hit by “cutting-edge smaller, lighter and diversified nuclear strike means.”

Late last month, the North Korean military’s Supreme Command said it had put its missile and artillery units at the highest level of combat readiness. In a special statement issued by the country’s government, parties and other organizations, the North also said the Korean Peninsula had entered a state of war.

Pyongyang has already declared that it would scrap the armistice agreement and inter-Korean nonaggression pacts.

By Song Sang-ho (sshluck@heraldcorp.com)