"The North's nuclear test, if it turns out to be true, could never be tolerated," he said.

Briefed on the possibility of the North's nuclear test, the sixth of its kind, at the meeting, Abe ordered Chief Cabinet Secretary Yoshihide Suga to gather and analyze information, immediately provide related information to the people and respond to the situation in cooperation with South Korea, the United States, China and Russia.

Chief of Staff of Japan's Self Defense Forces Katsutoshi Kawano told reporters, "(The government) is checking it now."

But an unidentified Japanese high-ranking official told Kyodo earlier in the day that the quake is sure to be the result of a nuclear test. (Yonhap)