Q: In this task, you are given a text of many news articles seperated by special token "|||||". Your task is to summarize them.
A North Korean soldier with a pair of the binoculars stands guard at the truce village of Panmunjom in the demilitarised zone separating the two Koreas, north of Seoul February 6, 2014. 
  
 A North Korean soldier, with a pair of binoculars, observes activity in the south of the truce village of Panmunjom in the demilitarised zone separating the two Koreas, north of Seoul February 6, 2014. 
  
 A North Korean soldier (top L) keeps watch as South Korean soldiers stand guard at the truce village of Panmunjom in the demilitarised zone separating the two Koreas, north of Seoul February 6, 2014. 
  
 A North Korean soldier keeps watch as a South Korean soldier stands guard at the truce village of Panmunjom in the demilitarised zone separating the two Koreas, north of Seoul February 6, 2014. 
  
 SEOUL A nuclear-capable U.S. B-52 bomber sortie over South Korea has endangered plans for reunions between families from the North and South of the country and risks triggering a further escalation of military tension, North Korea said on Thursday. 
  
 North Korea said a flight by the nuclear-capable B-52 took place off the west coast of the Korean peninsula on Wednesday. 
  
 A U.S. military spokeswoman said she could not discuss details of specific missions, adding: "The U.S. Pacific Command has maintained a rotational strategic bomber presence in the region for more than a decade." 
  
 A South Korean military source told the Yonhap news agency that the flight was a training sortie involving a single aircraft. The North's National Defence Commission, the country's top military body, said in a statement read on state television, that it was a rehearsal for a nuclear attack. 
  
 "At the time when the agreement was made on reunions of separated families and relatives at Panmunjom, a formation of U.S. B-52 strategic bombers from Guam was carrying out nuclear strike practices all day over Korea's west sea, aiming at us," a spokesman for the Commission was quoted as saying. 
  
 In a rare confidence-building move, the two Koreas agreed on Wednesday, in talks at the border village of Panmunjom, to allow families still divided by the 1950-53 Korean War to meet for five days in late February for the first time since 2010. 
  
 South Korea's Ministry of Unification said it would be "regrettable" and would hurt separated families if North Korea did not go ahead with the reunions as agreed in response to the flight. 
  
 A sharp escalation of tension between the North and South in early 2013 triggered threats by the North of a nuclear strike on South Korea, Japan, the U.S. South Pacific territory of Guam and even the continental United States. Washington responded with B-2 and B-52 flights over South Korea. 
  
 Both aircraft can carry nuclear weapons. 
  
 The North has made a diplomatic push to try and halt U.S. and South Korean drills that are regularly staged at this time of year, although the South said on Thursday the drills would go ahead as planned. 
  
 Hazel Smith, a North Korea expert at Britain's University of Central Lancashire said she expected North Korea to respond to the sortie. 
  
 "Since North Korea is motivated by military thinking, a show of force is probably going to provoke a response," she said. 
  
 Smith said any one of various groups in North Korea might try to make a show of power with a reaction to the flight, and young leader Kim Jong Un was probably unable to influence events. 
  
 "There is no political manager at the top of this - you need someone in an authoritarian country to manage the elite, and Kim Jong Un does not have the legitimacy, authority or experience to manage these different interests," Smith said. 
  
 "I have never seen such an internally unstable political situation in North Korea," said Smith, who has been researching the country for more than 25 years. 
  
 (Reporting by Ju-min Park and James Pearson; Editing by David Chance and Robert Birsel) ||||| Image copyright AFP Image caption Divided families meet briefly at the reunions before returning to their respective homes 
  
 North Korea has threatened to cancel family reunions with the South, a day after agreeing to hold them. 
  
 Its top military body said in a statement that it would reconsider the deal if joint US-South Korea military exercises went ahead. 
  
 "Dialogue and exercises of war" could not go hand in hand, South Korea's Yonhap news agency quoted the North Korean statement as saying. 
  
 The two Koreas last held reunions for divided families in 2010. 
  
 The next reunions - for family members separated when the Korean peninsula was partitioned at the end of the 1950-53 Korean War - are scheduled for 20 February. 
  
 In the past North Korea has cancelled reunions after the South took actions it opposed. 
  
 It has been accused of using the reunions, which are highly emotional events, as a bargaining chip. 
  
 'Proceed as normal' 
  
 "As we were reaching an agreement on the separated families, B-52 bombers were engaging in nuclear strike drills against us above Korea's western sea," the statement from North Korea's National Defence Commission said. 
  
 Analysis If celebration over the family reunions was muted here in South Korea on Wednesday, this is why. North Korea's track record of sticking to its agreements is not good. It cancelled last year's reunions at short notice, after Seoul refused to tie them to inter-Korean economic projects. And 24 hours after it was announced, this latest glimmer of co-operation seems to have been snuffed out too. The reasons given were well-worn: slander against the dignity of the North Korean state, and military training drills - apparently involving a nuclear-capable B-52 bomber. But US and South Korean forces here routinely warn Pyongyang of any training drills in advance. If that was indeed the case, the North would have known about the exercise before it sat down to negotiate on Wednesday. Large-scale military exercises planned for later this month were always seen as a potential snag in the plans. Last year, similar drills contributed to a rapid rise in tension here. And this year, they are due to begin around the same time as the reunions. No wonder many South Koreans remain cautious. 
  
 "As long as [South Korea] hurts our dignity and slanders our regime, we can't help but reconsider fulfilling the agreement," the statement added. 
  
 Seoul's Defence Ministry refused to comment on the activities of American assets, the BBC's Lucy Williamson in Seoul reports. 
  
 But South Korea's main news agency said the drill had involved one B-52 aircraft training along the country's south-western coastline, our correspondent adds. 
  
 Major US and South Korea military drills, which are held every year around this time, are due to begin later this month. The exercises anger Pyongyang, which views them as aggressive. 
  
 Last year, the exercises led to a prolonged surge in tensions, with North Korea threatening pre-emptive nuclear strikes and cutting a military hotline with the South. 
  
 A South Korean Defence Ministry spokesman said on Thursday that the joint drills would go ahead. 
  
 "We will proceed with our drills normally, regardless of the reunions for separated families," said ministry spokesman Kim Min-seok. 
  
 It is estimated that there are about 72,000 South Koreans - nearly half of them aged over 80 - on the waiting list for a chance to join the family reunion events. 
  
 Millions were separated from their families by the division of the Korean peninsula after the 1950-1953 war. 
  
 The programme was suspended after the North's shelling of a South Korean border island in November 2010. |||||
A:
Well, that was fast. North Korea is already threatening to call off a reunion for families separated by the Korean War that it agreed to only yesterday, in response to a US bomber sortie over South Korea. "As we were reaching an agreement on the separated families, B-52 bombers were engaging in nuclear strike drills against us," North Korea's National Defense Commission said, according to the BBC's translation. "As long as [South Korea] hurts our dignity … we can't help but reconsider fulfilling the agreement." South Korea's main news agency says a single B-52—not a formation, as the North alleged—performed a training mission off the coast. But the flight is minor compared to South Korea's annual joint military drills with the US, which are scheduled to begin later this month. Similar drills scuttled a planned reunion last September. "Since North Korea is motivated by military thinking, a show of force is probably going to provoke a response," one North Korea expert tells Reuters, possibly including a reciprocal show of force.