TOKYO (Sputnik) — Earlier in the day, South Korean media reported an earthquake near the North Korean nuclear facility, prompting Seoul's suspicions that Pyongyang had performed another nuclear test. Later, North Korea confirmed that it had indeed tested a hydrogen bomb, which it said was a success.
"This [test] is a serious threat to our country's security and cannot be justified in any way. I strongly condemn it," Abe said, as quoted by Kyodo news agency.
He added that the North Korean move was a violation of the UN Security Council's resolutions and a challenge to nuclear non-proliferation.
On December 10, North Korean leader Kim Jong Un said that North Korea had a hydrogen bomb and was ready to use it to protect its sovereignty.
In 2003, Pyongyang withdrew from the international Nuclear Non-Proliferation Treaty, a deal that was intended to prevent the making and use of nuclear weapons.