This follows threats from Pyongyang last week both to end the armistice and to 'exercise the right to a preemptive nuclear attack.'
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As the United States and South Korea launched its two-week long "Key Resolve" war games today, North Korea followed through on two of its threatened responses – cutting off a hotline and "blowing apart" the armistice between North and South.
South Korea's Unification Ministry, which handles relations with the North, confirmed this morning that the hotline between Pyongyang and Seoul appears to have been cut off, reports Agence France-Presse. "The North did not answer our call this morning," a ministry official said.
And Rodong Sinmun, the newspaper of the North's ruling Communist Party, wrote Monday that the Korean War armistice, which ended hostilities between North and South but did not entail a formal peace agreement, was at a "complete end."
"With the ceasefire agreement blown apart... no one can predict what will happen from now on," the newspaper wrote.
Neither of today's moves are unexpected, or indeed new. AFP notes that the hotline has been cut off five times since its installation in 1971, most recently in 2010, and that the North has "voided" the armistice nearly a dozen times in the past 20 years, the last time in 2009.
But the moves follow days of hyperbolic language from Pyongyang, which threatened last week both to end the armistice and to "exercise the right to a preemptive nuclear attack to destroy the strongholds of the aggressors" like the US and South Korea. The threats, made both in response to new United Nations Security Council sanctions against North Korea over its nuclear weapons test last month and in anticipation of today's war games, have increased tensions across the region. And with more than 10,000 South Korean and 3,500 American troops mobilizing for the annual "Key Resolve" simulations, there is concern about accidental escalation.
BBC News reports that there is a heightened sense of concern among portions of the South Korean population, particularly among older South Koreans, due to the newness of both North Korea's recently ascended leader Kim Jong-un and South Korea's President Park Geun-hye, who was sworn in two weeks ago.
"I didn't care about this issue until now," one South Korean told the BBC. "But I do worry this time around. The young North Korean leader is not strong, and I don't trust the new government here in the South."
Ms. Park's new government has been particularly vocal in its threats against the North – it said it would target the North's top command should any attacks be made against the South – in what John Delury, a professor of International Studies at Seoul's Yonsei University, told the BBC was a kind of "pre-emptive rhetorical deterrence."
The idea that strong words could act as a deterrent to North Korean actions has gained traction since the lethal shelling of South Korea's Yeonpyeong Island in 2010.
As a government, Prof Delury says: "You're always fighting the last battle, and the last battle for South Korea was Yeonpyeong. The perception then was that North Korea had got away with shelling the island."
By talking tough, he believes Park Geun-hye wants to avoid any initial attack by the North.
But, he said, "some South Koreans are worried that the wrong lessons have been learned, and that if something small happens, it could escalate because the South Korean government doesn't want to be accused of doing nothing."
The two Koreas continue to have at least two working channels of communication between their militaries and aviation authorities.
One of those hotlines was used Monday to give hundreds of South Koreans approval to enter North Korea to go to work. Their jobs are at the only remaining operational symbol of joint inter-Korean cooperation, the Kaesong industrial complex. It is operated in North Korea with South Korean money and knowhow and a mostly North Korean work force....
"If South Koreans don't go to work at Kaesong, North Korea will suffer" financially, said analyst Hong Hyun-ik at the private Sejong Institute in South Korea. "If North Korea really intends to start a war with South Korea, it could have taken South Koreans at Kaesong hostage."