A South Korean amphibious assault vehicle, left, moves to a landing ship as a South Korean submarine, center, is seen from the southeastern port of Pohang on March 7. (AFP via Getty Images)

The United States and South Korea kicked off major military exercises on Monday, including rehearsals of surgical strikes on North Korea’s main nuclear and missile facilities and “decapitation raids” by special forces targeting the North’s leadership.

The drills always elicit an angry response from Pyongyang, but Monday’s statement was particularly ferocious, accusing the United States and South Korea of planning a “beheading operation” aimed at removing Kim Jong Un’s regime. The North Korean army and people “will take military counteraction for preemptive attack so that they may deal merciless deadly blows at the enemies,” the North’s powerful National Defense Commission said in a statement.

The exercises come at a particularly tense time, with the international community — especially the United States and South Korea — looking to punish Pyongyang for its recent nuclear test and missile launch. The United Nations last week imposed its toughest sanctions yet on the North, and South Korean President Park Geun-hye is expected to unveil further, unilateral sanctions on Tuesday.

About 17,000 American forces and 300,000 South Korean personnel — a one-third increase from last spring’s drills — will take part in 11 days of computer-simulated training and eight weeks of field exercises, which will involve ground, air, naval and special operations services.

A state-run North Korean television agency spoke out on March 7 ahead of military drills from the U.S. and South Korea, saying the U.S. will be "held accountable for igniting the war." (Reuters)

The exercises will revolve around a wartime plan, OPLAN 5015, adopted by South Korea and the United States last year. The plan has not been made public but, according to reports in the South Korean media, includes a contingency for surgical strikes against the North’s nuclear weapons and missile facilities, as well as “decapitation” raids to take out North Korea’s leaders. The JoongAng Ilbo newspaper reported that Kim Jong Un would be among them.

The joint forces will also run through their new “4D” operational plan, which details the allies’ preemptive military operations to detect, disrupt, destroy and defend against North Korea’s nuclear and missile arsenal, the Yonhap News Agency reported. “The focus of the exercises will be on hitting North Korea’s key facilities precisely,” a military official told the wire service.

Christopher Bush, a spokesman for U.S. Forces Korea, declined to comment on the reports. “Alliance operational plans are classified, and we aren’t authorized to discuss them for operations security reasons,” he said.

USFK said in a statement that it had informed the North’s Korean People’s Army — through the U.N. Command, which controls the demilitarized zone between the two Koreas — about the exercise dates and “the non-provocative nature of this training.”

But North Korea apparently did not see it this way.

“We have a military operation plan of our style to liberate south Korea and strike the U.S. mainland ratified by our dignified supreme headquarters,” the North’s National Defense Commission said in its statement, carried by the official Korean Central News Agency.

It said it had deployed “offensive means” to strike South Korea and “U.S. imperialist aggressor forces bases in the Asia-Pacific region and the U.S. mainland.”

“If we push the buttons to annihilate the enemies even right now, all bases of provocations will be reduced to seas in flames and ashes in a moment,” the commission said.

North Korea is particularly sensitive to suggestions of attacks on Kim — as the furor surrounding the 2014 Hollywood film “The Interview” showed — and it has a habit of making threats on which it cannot follow through.

Last week, Kim ordered his military to be ready to use its nuclear weapons at any time, saying they were needed, given the “ferocious hostility” of new “gangster-like” sanctions imposed on Pyongyang.

The threats issued Monday were “absolutely not credible,” said Daniel Pinkston, a former Korean linguist with the U.S. Air Force who teaches at Troy University’s campus in Seoul.

“They would trigger everything North Korea wants to avoid, which is their absolute destruction in retaliatory attacks,” Pinkston said. “Second, if you are going to launch an attack against a much stronger adversary, why would you telegraph that? You’d want the element of surprise.”

Much of North Korea’s rhetoric is for domestic consumption, as Kim tries to burnish his leadership credentials ahead of a much-anticipated Workers’ Party congress in May, the first in 36 years.

Kim, however, has shown himself willing to use the means available to him to express his anger. Last year, during a period of increased tensions with South Korea, he ordered his military onto a war footing, sending army units to the demilitarized zone and submarines out of port.

South Korea and the United States said they will increase monitoring of North Korea during the exercises.

“We will carry out these exercises while keeping tabs on signs of North Korean provocations,” a South Korean official told reporters. “If the North provokes us during this exercise, the U.S. and our troops will retaliate with an attack ten-fold stronger.”

About 28,500 American troops are stationed in South Korea, the result of an security alliance formed during the Korean War.

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