[25] The Russian Defence Ministry confirmed it had detected a nuclear detonation in North Korea and was analysing the data to determine the yield.

[27][28] Geophysical Service of the Russian Academy of Sciences has registered underground nuclear explosion conducted in North Korea on 25 May 2009.

[29] In China, tremors were felt in the prefecture of Yanbian, which borders North Korea, and forced students in some local schools to be evacuated.

[citation needed] The U.S. intelligence community assessed that North Korea "probably" had conducted a nuclear test with a yield of "a few kilotons".

[7][8] Hans M. Kristensen of the Federation of American Scientists cautioned that "early news media reports about a 'Hiroshima-size' nuclear explosion seem to be overblown".

[41] The South Korean news agency Yonhap cited military officials as saying that the launches seemed to be aimed at keeping U.S. and Japanese surveillance planes away from the site.

A military spokesman quoted by official media said that North Korea could no longer guarantee the safety of shipping off its west coast, suggesting a missile could also be fired in that direction.

[49][50] This was reaffirmed on 1 June 2009 by Defense Secretary Robert M. Gates who said at a news conference with his Philippine counterpart during a brief visit to Manila "We have seen some signs that they may be doing something with another Taepodong-2 missile, but at this point it's not clear what they're doing".

In addition, a South Korean defence ministry spokesman said that signs that North Korea was preparing to fire an intercontinental ballistic missile (ICBM) had been detected.

North Korea apparently has moved the ICBM to a new base in Dongchang-ri along its west coast and a launch could take place in one or two weeks, according to Yonhap.

[11] South Korea's Yonhap news agency reported citing KCNA that citizens of Pyongyang held a rally to celebrate the country's second successful nuclear test on 26 May.

[80] In Japan a policy debate ensued regarding strengthening its military up to and including the possibility of an independent pre-emptive strike capability and even nuclear armaments, subjects hitherto taboo.

[81][82] On 30 May, the United Kingdom's Ministry of Defence confirmed that a VC10 tanker plane, which is used for air-to-air refueling, had been sent to Kadena Air Base in Okinawa, Japan to help support the investigations, led by the U.S. military, to determine the power of the nuclear explosion and the type of material that was used.

The delegation also includes Stuart Levy, the Treasury under-secretary for terrorism and financial intelligence, and Admiral James Winnefeld of the Joint Chiefs of Staff.

[88] On the same day, as a response to the increased activity of the N. Korean military and after reports that North Koreans have stepped up naval drills near the western sea border, the site of deadly skirmishes between the two Koreas in 1999 and 2002, South Korea deployed a high-speed naval vessel, the Yoon Youngha guided missile patrol boat, to the area and vowed to "punish" any attacking forces.

[89][90] After the North Korean nuclear test the U.S. has approved the sale of a number of weapon systems to South Korea, including GBU-28 "bunker buster" bombs, SM-2 Standard surface-to-air Missiles and F-16 Block 32 Aircraft Upgrades improving the aircraft and increasing the South Korean military's operational abilities.

[94] The United Nations Security Council unanimously adopted resolution 1874 in response to the test, imposing further economic sanctions on the country and authorising UN member states to inspect North Korean cargo and destroy any that may be involved in the nuclear weapons program.