An artificial earthquake has been detected in North Korea, in a possible indication that the country has carried out its third underground nuclear test, South Korea's Yonhap News Agency reported Tuesday morning.
Yonhap said a magnitude 5.1 artificial quake was detected in North Korea northeastern county of Kilju at 11:58 a.m.
It quoted a South Korean foreign ministry official as saying there is a "high possibility" that North Korea has carried out a nuclear test.
"At this point, the seismic activity of artificial earthquake appears to indicate a nuclear test by North Korea," the official said.
Yonhap said President Lee Myung Bak has convened a meeting of the National Security Council to deal with the matter, while it has also stepped up military readiness.
At a Monday press conference Japan's Chief Cabinet Secretary Yoshihide Suga said Japan's meteorological agency detected an earthquake that may have been caused artificially around noon.
"Referring to past cases, we believe it may have been caused as a result of North Korea's nuclear test," he said.