YONHAP NEWS

(LEAD) N. Korea conducts second nuclear test following rocket launch

   By Sam Kim
SEOUL, May 25 (Yonhap) -- North Korea said Monday it successfully carried out a second nuclear test to bolster the "might" of its arms, less than two months after it launched a rocket that neighbors fear could be turned into a ballistic missile capable of hitting the U.S.

   Its official media said the test was "successful" and "helped satisfactorily settle the scientific and technological problems" that may have surfaced after it conducted its first test in October 2006.

   South Korea said its weather agency detected tremors of "an artificial earthquake" measuring at 4.4 on the Richter magnitude scale in the northeastern part of the communist neighbor at 9:54 a.m. The agency initially said it measured 4.5.

   The 2006 test registered a magnitude of 3.6, according to South Korean officials.

   The Joint Chiefs of Staff said North Korea coupled the latest underground detonation with a short-range missile test launched from the same coastal base that it used to conduct its April 5 rocket launch.

   A North Korean diplomat in Moscow threatened his country may step up its nuclear testing "if the U.S. and its allies continue their policy of intimidation," Itar-Tass news agency reported.

   The U.S. refrained from confirming the North Korean announcement, but President Barack Obama called the situation "a threat to international peace."

   "The danger posed by North Korea's threatening activities warrants action by the international community," he said.

   Russia said the "nuclear" blast appears to have had a force of up to 20 kilotons, according to its state media. A nuclear test is considered successful if it produces a yield of 5-15 kilotons. The U.S. believes the North's 2006 explosion yielded less than a kiloton.

   A kiloton is equivalent to 1,000 tons of TNT.

   "The current nuclear test was safely conducted on a new higher level in terms of its explosive power and technology of its control," the North's Korean Central News Agency said, monitored in Seoul.

   The test, which South Korea said appears to have taken place in Poongkye-ri, North Hamgpyong Province -- the site of the 2006 blast -- was aimed at "further increasing the power of nuclear weapons and steadily developing nuclear technology," the report said.

   "The nuclear test is a serious threat to peace and stability on the Korean Peninsula," South Korean presidential spokesman Lee Dong-kwan said in a statement, calling it "intolerable" and "a serious challenge to the international regime on nuclear non-proliferation."

   The Unification Ministry in Seoul temporarily barred its nationals from traveling to the communist neighbor, with the exception of those traveling on business to the joint industrial complex in the North Korean border city of Kaesong.

   In a meeting with his Japanese counterpart Hirofumi Nakasone, South Korean Foreign Minister Yu Myung-hwan agreed to push for a U.N. Security Council emergency meeting, while the defense ministry in Seoul placed its 655,000 troops on a heightened alert.

   Chinese Foreign Minister Yang Jiechi, in his talks with Yu, urged that regional peace and stability be given top priority in dealing with North Korea's action. Diplomatic sources said Pyongyang gave Beijing prior notice of its nuclear test.

   Since the U.N. Security Council condemnation of its rocket launch, North Korea has threatened additional nuclear and missile testing, vowing to toughen its "nuclear deterrent against U.S. hostilities."

   Pyongyang claims it put a satellite in orbit with the launch while Seoul and Washington say nothing entered space, calling the move a provocative test of long-range ballistic missile technology.

   South Korean and U.S. experts downplay the ability of the communist regime to tip its intercontinental ballistic missiles with nuclear bombs.

   Protesting the international objection to its rocket launch, North Korea has vowed to jettison the six-nation denuclearization-for-aid talks and expelled outside monitors from its nuclear facilities.

   The North is believed to have plutonium enough to create up to six nuclear bombs. It has vowed to restore its Yongbyon nuclear reactor, which had been undergoing disablement under a pact signed by the two Koreas, the U.S., Japan, Russia and China.

   Yang Moo-jin, a professor at the University of North Korean Studies in Seoul, said North Korea is stepping up its pressure on Washington so it can squeeze "maximum" concessions.

   Its leader Kim Jong-il also knows that U.N. sanctions, imposed after the 2006 test, would have little economic impact on his already isolated country, Yang said.

   "Kim is following his roadmap under meticulous calculations," he said. "After the sanctions and temporary condemnations, he is looking at maximizing profits North Korea may get by holding nuclear disarmament talks with the U.S."

   Yang added North Korea appears to be expecting increased internal military unity as a result of the nuclear test.

   South and North Korea remain technically at war after the 1950-53 Korean War ended in a truce rather than a peace treaty. Their ties deteriorated to their worst level in a decade after President Lee Myung-bak took office in Seoul early last year with a pledge to tie reconciliation to North Korean efforts to disarm.

   The latest test came hours after Kim Jong-il sent condolences over the death of former South Korean President Roh Moo-hyun, who leapt from a cliff on Saturday amid pressure from a corruption scandal involving his confidants and family.

   Roh and Kim met in Pyongyang in 2007 for the second-ever summit between the two countries. The first was held in 2000, leading to a series of reconciliatory projects, including the Kaesong complex.

   South Korea's stock and currency markets briefly tumbled after the North Korean announcement of a nuclear test, but recovered most of their earlier losses.

   The benchmark Korea Composite Stock Price Index (KOSPI) fell 2.85 points, or 0.2 percent to 1,400.90. The local currency closed at 1,249 won to the U.S. dollar, down 1.6 won from Friday's close.

   samkim@yna.co.kr
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