North Korea detonated its fifth atomic device on Friday, South Korean officials said, with Seoul and international monitors detecting unusual seismic activity near the North’s northeastern nuclear test site.
South Korea’s Joint Chiefs of Staff said in a statement that “artificial seismic waves” from a quake measuring 5.0 were detected near the Punggye-ri test site.
World leaders responded to the suspected nuclear test with immediate effect.
Japan’s chief government spokesman said Tokyo will consider further unilateral sanctions against North Korea what South Korea said was a nuclear test.
“North Korea’s nuclear development is a grave threat to Japan’s safety,” Chief Cabinet Secretary Yoshihide Suga told a news conference.
US President Barack Obama and South Korean President Park Geun-hye spoke by telephone on Friday about the nuclear test, South Korea’s presidential office said.
South Korea’s presidential office said US President Barack Obama had indicated he would take every action under a mutual defence treaty with the South, including providing its nuclear umbrella, to protect Seoul from any North Korean threat.
Obama later said provocative actions by North Korea will be met with “Serious consequences”. He reiterated the “unbreakable” US commitment to security of allies in Asia and the world.
Obama and Park talked for fifteen minutes from 0100 GMT while Obama was on Air Force One on his way back to the United States from a regional summit in Laos, according to the South Korean presidential office.
China’s environment ministry has also begun emergency radiation monitoring along border regions in northeastern China after the suspected nuclear test, state television said on its official microblog on Friday.
The 5.0 magnitude earthquake Friday is the largest of the four past quakes associated with North Korean nuclear tests, according to South Korea’s weather agency. Artificial seismic waves measuring 3.9 were reported after North Korea’s first nuclear test in 2006; 4.8 was reported from its fourth test this January.