Outgoing South Korean President Lee Myung-bak sees signs that North Korea will explode more than one device in the atomic trial that is widely expected to occur at any time, Agence France-Presse reported on Tuesday.
Pyongyang has suggested it will conduct a "higher level" atomic trial after being hit with toughened U.N. Security Council sanctions last month. The 15-nation body was responding to the North's December launch of a space rocket, which flouted international rules against the Stalinist state's use of ballistic missile technology.
Lee told the Chosun Ilbo newspaper that the "higher level" description of the coming test indicated plans to blow up more than one nuclear device. "North Korea is likely to carry out multiple tests at two places or more simultaneously" for the purposes of extracting as much data as possible, he said.
New U.S. Secretary of State John Kerry reached agreement with his South Korean opposite, Kim Sung-hwan, in a telephone conversation that should North Korea continue "its provocative behavior and takes further steps, that there must be further consequences," State Department spokeswoman Victoria Nuland said on Monday in an Associated Press report.
The two longtime allies have been swapping views on possible new U.N. penalties should the North carry out another nuclear trial blast, anonymous government officials in Seoul told the Yonhap News Agency on Tuesday.
Many issue experts think there is a good chance the event will involve the detonation of at least one highly enriched uranium-fueled device. North Korea used plutonium in its two prior tests in 2006 and 2009.
However, conclusively determining whether HEU material or plutonium is used will be difficult for the international scientific community, U.S. nuclear weapons expert Siegfried Hecker told the New York Times.
Determining whether plutonium or uranium has been used in a nuclear explosion is typically done by detecting and examining the varying kinds of xenon gas emissions that are released. This has to be done quickly, according to the Times.
"The problem with xenon gases is that after 10 to 20 hours after the detonation, it gets extremely difficult to tell their ratio difference between a plutonium and atomic bomb," an unidentified atomic specialist with ties to the South Korean armed forces said in an interview. "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."
"If a next test is well contained, then we may learn nothing about the device detonated," Hecker wrote in an online post for Foreign Policy magazine on Tuesday. "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."
The North on Tuesday delivered a new nuclear threat against its foes, Reuters reported.
"The D.P.R.K. has drawn a final conclusion that it will have to take a measure stronger than a nuclear test to cope with the hostile forces nuclear war moves that have become ever more undisguised," according to the official Korean Central News Agency.
Pyongyang caught people's attention in a different fashion this week with the official release of a video in which a man dreams of a devastating rocket attack on New York City, to the tune of "We Are The World."