South Korea’s military has increased its monitoring of North Korea after the secretive state claimed a successful test of a miniaturized hydrogen device. The fourth nuclear test by Pyongyang was condemned by leading nations.
READ MORE: North Korea claims fully successful ‘miniaturized hydrogen bomb’ test
"North Korea's provocation is in clear violation of Security Council resolutions and a serious challenge to international peace and security," Seoul's Vice Foreign Minister Lim Sung-nam said during an emergency meeting of ministry officials, according to Yonhap.
South Korea claims it will seek to cooperate with regional partners and make North Korea pay a price for its provocation.
President Park Geun-hye chaired an emergency National Security Council session. In remarks published on her website the president said the country will take decisive measures against any additional provocations by North Korea and "closely cooperate with the international community to make sure that North Korea pays the corresponding price" for its latest test.
READ MORE: N. Korea could have up to 20 nuclear warheads – Chinese sources
In a “special and important” announcement at noon, North Korean TV claimed that the country had successfully detonated a miniature hydrogen bomb, marking the country’s fourth known nuclear test. The announcement followed the detection of an “artificial seismic event” in the vicinity of a known Pyongyang nuclear site.
Mastering a hydrogen nuclear device would be a major breakthrough for North Korea. The technology allows scaling up the yield of a nuclear device with few limitations.
The claimed miniaturization of a nuclear device may mean that North Korea could soon develop a nuclear warhead for its larger ballistic missiles. Pyongyang has already claimed it can deliver nuclear strikes on the US mainland, but military experts doubt they have such a capability.
Nations throughout the world rallied to criticize North Korea for the apparent escalation of its nuclear weapons program.
The Russian Foreign Ministry said the reported nuclear test by North Korea could cause an escalation of tension in the Korean Peninsula and called for restraint. It added that analysis of data pertaining to the alleged test was still in progress.
The White House said the US will continue to "protect and defend our allies in the region," and will "respond appropriately to any and all North Korean provocations." It stressed that it can't confirm that the device detonated was actually a hydrogen bomb, as claimed by Pyongyang.
The location and nature of seismic activity reported in North Korea is consistent with previous nuclear tests conducted by Pyongyang, US government sources told Reuters.
US agencies are checking all available sensors to try to verify the exact nature of the event and – if it was a nuclear test – what kind of device was involved, the unnamed sources said.
China will work with the international community to further the cause of the denuclearization of the Korean Peninsula, Hua Chunying, spokesperson for the Chinese Foreign Ministry, said during a daily briefing. She added Beijing had no advanced knowledge of the planned test and firmly opposed North Korea's move.
Japanese Prime Minister Shinzo Abe condemned the developments, making it clear that Tokyo will “absolutely” not tolerate threats against its national security and would issue a firm response to North Korea's challenge against nuclear non-proliferation.
India voiced deep concern over the developments, saying it would negatively affect stability in the region.
UK Foreign Secretary Philip Hammond said North Korea's move is a "provocation which I condemn without reservation" and a "grave breach" of UN Security Council resolutions. The top British diplomat is currently in Beijing on a two-day trip. He noted that no confirmation of a nuclear test was immediately available.
France said the reported hydrogen bomb test was "an unacceptable violation of Security Council resolutions" and called for a "strong reaction from the international community" in a statement released by President Francois Hollande's office.
Australia condemned the test “in the strongest possible terms,” saying the move was “provocative and dangerous,” the country's department of foreign affairs said in a statement published on its website.
The UN Security Council is to address the possible nuclear test on Wednesday, at 4:00pm GMT, at a request from the US and Japan.