Detailed Instructions: In this task, you are given a text of many news articles seperated by special token "|||||". Your task is to summarize them.
Q: N. Korea video shows US city under attack 
  
 SEOUL — North Korea, poised to conduct a nuclear test any day now, has posted a video on YouTube depicting a US city resembling New York engulfed in flames after an apparent missile attack. 
  
 The footage was uploaded Saturday by the North's official website, Uriminzokkiri, which distributes news and propaganda from the state media. 
  
 The video is shot as a dream sequence, with a young man seeing himself on board a North Korean space shuttle launched into orbit by the same type of rocket Pyongyang successfully tested in December. 
  
 As the shuttle circles the globe -- to the tune of "We Are the World" -- the video zooms in on countries below, including a joyfully re-unified Korea. 
  
 In contrast, the focus then switches to a city -- shrouded in the US flag -- under apparent missile attack with its skyscrapers, including what appears to be the Empire State Building, either on fire or in ruins. 
  
 "Somewhere in the United States, black clouds of smoke are billowing," runs the caption across the screen. 
  
 "It seems that the nest of wickedness is ablaze with the fire started by itself," it added. 
  
 The video ends with the young man concluding that his dream will "surely come true". 
  
 "Despite all kinds of attempts by imperialists to isolate and crush us... never will anyone be able to stop the people marching toward a final victory," it said. 
  
 The North is expected to conduct its nuclear test as a defiant response to UN sanctions imposed after its December rocket launch. 
  
 Copyright © 2013 AFP. All rights reserved. More » ||||| But to find out which type of bomb is used, “you have to be very lucky,” said Siegfried S. Hecker, a former director of the Los Alamos National Laboratory in New Mexico and now a professor at Stanford University in California. He was speaking on the sidelines of a forum organized by the South Korean news agency Yonhap and the Shorenstein Asia-Pacific Research Center at Stanford. 
  
 Though scientists can determine the size of a bomb from its seismic signals, determining whether it is made of plutonium or highly enriched uranium requires quick detection and analysis of the different types of xenon gases produced in an atomic explosion. 
  
 “The problem with xenon gases is that 10 to 20 hours after the detonation, it gets extremely difficult to tell their ratio difference between a plutonium and atomic bomb,” said a nuclear scientist affiliated with the South Korean military, speaking on the condition of anonymity because he was not allowed to talk on the record. “Since North Korea conducts its nuclear tests underground, it takes two to four days for the gases to get out, if they do at all. By then, it would be too late to tell the difference.” 
  
 Dr. Hecker shared the concern. 
  
 “If a next test is well contained, then we may learn nothing about the device detonated,” he said in an article posted Tuesday on the Web site of Foreign Policy magazine. “However, one of the risks Pyongyang takes in trying to demonstrate a test at a higher level is that they may produce fissures that allow radioactive seepage, or possibly cause a major blowout from the tunnel.” 
  
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 American officials said they relied on offshore airborne monitors and radiological monitoring stations around the world to detect leaking gases in the 2006 test, but did not specify whether it was a plutonium or a uranium device. In the 2009 test, when the tunnel used at the time was believed to have been sealed, there was no report of leaked gases. 
  
 After the United Nations Security Council voted on Jan. 22 to tighten sanctions against North Korea as punishment for its most recent rocket launching, on Dec. 12, the North vowed to expand its nuclear program “both quantitatively and qualitatively” and conduct a third nuclear test at a “higher level.” 
  
 Dr. Hecker visited the North’s Yongbyon nuclear complex in 2010, and after years of denying its existence, North Korea revealed to him a uranium enrichment facility. He said he believed that North Korea must have another such facility, still hidden. A former United States defense secretary, William J. Perry, speaking during the forum in Seoul on Tuesday, said there were “at least two” uranium enrichment facilities in the North. 
  
 Unlike a plutonium program, which involves a highly visible nuclear reactor, centrifuge plants can be easily hidden in North Korea’s estimated 8,000 underground military installations, South Korean military officials said. 
  
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 Another possibility is that North Korea could detonate two or more nuclear devices at the same time, Lee Myung-bak, the South Korean president, told the South Korean daily Chosun Ilbo in an interview published Tuesday. 
  
 The North Koreans have been active around two of the three known portals to underground tunnels at Punggye-ri, in northeastern North Korea, David Albright and Robert Avagyan of the Institute for Science and International Security, a Washington-based group that tracks nuclear proliferation, said in an analysis of recent satellite imagery posted Monday on the group’s Web site. 
  
 The North’s two previous bomb tests were considered less than successful, and it needed to conduct more tests to collect information on miniaturizing bombs to mount on its missiles, analysts said. 
  
 “By a ‘nuclear test of higher level,’ the North Koreans meant their efforts to miniaturize their nuclear devices,” Mr. Lee told Chosun. “They become a real threat if they send such miniaturized nuclear weapons to Iran or mount them on intercontinental ballistic missiles.” |||||
A:
If you think North Korea harbors a not-so-secret desire to obliterate the US—while backed by a Michael Jackson song—you'd be sort of correct. The country's official website uploaded a truly bizarre YouTube video on Saturday in which a slumbering man dreams of a rocket blasting a space shuttle into orbit; as it circles the globe, the dreamer can see what's happening on Earth. At one point, the American flag appears, followed by images of a New York-esque city (the AFP spots what appears to be the Empire State Building) being bombed and burning, before the shuttle zooms out and into a shower of sparkles. Yes, seriously. And yes, the whole thing is set to an instrumental version of "We Are the World." The AFP translates some of the many captions that appear, including "It seems that the nest of wickedness is ablaze with the fire started by itself" and the dreamer concluding his vision will "surely come true." In other North Korea news: The nuke watch continues, and South Korea's UN ambassador says the test draws nigh. The AP reports that Kim Sook yesterday said it "seems to be imminent," a determination based on the observation that there are "very busy activities" taking place at the Punggye-ri test site. Should that test occur, we might have a tough time determining whether a plutonium or uranium device was detonated, reports the New York Times. In order to figure that out, the xenon gases spawned by the explosion must be analyzed, but the prime window for doing so closes about 20 hours following detonation—and the underground nature of the test means it could take as many as four days for the gases to reach the surface. As a former Los Alamos lab director explains, "You have to be very lucky." One "lucky" possibility? "In trying to demonstrate a test at a higher level ... they may produce fissures that allow radioactive seepage." One other possibility: North Korea may be planning two nuke tests.