Tensions between North and South Korea have risen to a new high this week as threatening rhetoric from the rivals rose to the highest level since North Korea took aim at a South Korean island in 2010.
Enraged over South Korea’s joint military drills with the United States, and recent approval of stricter sanctions by the U.N, Pyongyang has continued its threat of imminent war, which includes vows to launch a nuclear strike on the U.S. and effectively nullifying the nearly 60-year-old armistice that ended the Korean War.
Seoul has responded to its northern rival with rhetoric of its own, and has placed its troops on high alert.
On Monday North Korea's main newspaper Rodong Sinmun reported that the armistice was nullified Monday as Pyongyang had previously announced. The North has also shut down a Red Cross hotline that the North and South used for general communication and the facilitation of aid shipments.
North Korea is also continuing large-scale military drills that Seoul says involve the army, navy and air force. The South Korean defense ministry said there have been no military activities it considers suspicious.
Despite the heightened tension, the two Koreas continue to have 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 at the Kaesong industrial complex are the only remaining operational symbol of joint inter-Korean cooperation. The complex is operated in North Korea, with South Korean money and a mostly North Korean work force.
More than 840 South Koreans aree set to cross the border Monday to Kaesong, which provides a badly-needed flow of hard currency to a country where many face food shortages, according to Seoul's Unification Ministry.
"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."
The escalating North Korean rhetoric can be traced to the approval of a new round of sanctions by the U.N. Security Council last week over Pyongyang's nuclear weapons test on February 12.
Analysts said that much of the rhetoric is designed to shore up loyalty among citizens and the military for North Korea's young leader, Kim Jong Un.
"This is part of their brinksmanship," said Daniel Pinkston, a Seoul-based expert on North Korea with the International Crisis Group think tank. "It's an effort to signal their resolve, to show they are willing to take greater risks, with the expectation that everyone else caves in and gives them what they want."
Part of what North Korea seeks is a formal peace treaty to end the Korean War, instead of the armistice that currently leaves the peninsula in a state of war. It also wants direct talks with Washington, recognition as a nuclear weapons state, and the removal of 28,500 U.S. troops stationed in South Korea.
Pinkston said there is little chance of fighting breaking out while war games are being conducted, but he added that he expects North Korea to follow through with a somewhat mysterious promise to respond at a time and place of its own choosing.
Among other threats in the past week, North Korea has warned Seoul of a nuclear war on the divided peninsula and said it was cancelling nonaggression pacts.
The vow to scrap the 1953 armistice is one the North has made previously, and it is believed to be incapable of making good on its threat to unleash a long-range nuclear missile on America.
North Korea has stated that the U.S. mainland is within the range of its long-range missiles, and an army general told a Pyongyang rally last week that the military is ready to fire a long-range nuclear-armed missile to turn Washington into a "sea of fire."
While outside scientists are still trying to determine specifics, the North's rocket test in December and third atomic bomb test last month may have actually pushed the country a step closer to acquiring the ability to strike the U.S. with nuclear weapons. Analysts, however, say Pyongyang is still years away from acquiring the smaller, lighter nuclear warheads needed for a credible nuclear missile program.
Still, South Korean and U.S. officials are monitoring Pyongyang's actions and noting that the North’s overall rhetoric has been more war-like than usual.
Under newly inaugurated President Park Geun-hye, South Korea's Defense Ministry has looked to send a message of strength in response to the latest comments from Pyongyang.
The ministry also has warned the North that its government would "evaporate from the face of the Earth" if it ever used a nuclear weapon. The White House also said the U.S. is fully capable of defending itself against a North Korean ballistic attack.
North Korea has a variety of missiles and other weapons capable of striking South Korea. The warship sinking and island shelling in 2010 occurred near a western sea boundary between the Koreas that North Korea fiercely disputes. It has been a recurring flashpoint between the rivals that has seen three other bloody naval skirmishes since 1999.
Kim was quoted as saying his military is fully ready to fight an "all-out war" and that he will order a "just, great advance for national unification" if the enemy makes even a slight provocation, according to the North's official Korean Central News Agency.