"This test surpasses all previous ones", Onodera said as quoted by the Nikkei newspaper.
Defense Secretary on Wednesday sought to downplay President Trump's earlier assertion that seemed to rule out a diplomatic solution to North Korea's ongoing missile tests.
A hydrogen bomb can achieve thousands of kilotons of explosive yield - massively more powerful than some 10 to 15 kilotons that North Korea's last nuclear test in September was estimated to have produced, similar to the bomb dropped on Hiroshima, Japan, in 1945. It said the underground test site did not leak radioactive materials, which would make such a determination even harder.
President Trump responded to the tests with a series of tweets, in which he dubbed North Korea a "rogue nation" and said its "words and actions continue to be very hostile and risky to the United States".
Juche is North Korea's homegrown ideology of self-reliance that is a mix of Marxism and extreme nationalism preached by state founder Kim Il Sung, the current leader's grandfather.
The latest quakes in North Korea are raising fears that the North is accelerating its nuclear test amid the growing tension on the Korean Peninsula.
The tremor's detection came hours after North Korean leader Kim Jong-un inspected the loading of a hydrogen bomb into a new intercontinental ballistic missile.
Later on Sunday Putin also had a phone call with Japan's Prime Minister Shinzo Abe and they both condemned Pyongyang's bomb test, Peskov said.
" North Korea is a rogue nation which has become a great threat and embarrassment to China, which is trying to help but with little success", he said.
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Blackman did not attempt any passes during game action against the Crimson Tide. "I still think we've got a great football team". He was taken to a medical tent on FSU's sideline and emerged with a brace on his left leg and using a pair of crutches.
The test came after propaganda pictures were published of Kim examining what was said to be a nuclear warhead being fitted on to the nose of an intercontinental ballistic missile.
Maria Zakharova, a spokeswoman for the foreign ministry, said that a search that U.S authorities carried out at Russia's diplomatic facilities was an attempt to prove that Moscow meddled in USA presidential elections, TASS state news agency reported.
Jiemiao Cangxin, a commentator on the Chinese microblog Weibo, said his building swayed so much that "I put my underpants on and I just ran, and when I reached the first floor I can say I wasn't the only one running away with just my underpants on!"
"We will convene a National Security council meeting to gather and analyse the information", CNN quoted Abe as saying.
Absent that understanding, China will continue to run out the clock until North Korea can strike US cities with nuclear weapons. The Korean People's Army or KPA is the North's military.
The Prime Minister refused to rule out future British military action against North Korea or cyber warfare after being quizzed by reporters four times on the issue.
North Korea has made no secret of its intention to develop the knowhow to launch a nuclear-tipped missile at the United States and has recently threatened the US Pacific territory of Guam.
"(Japan) sternly protests North Korea and condemns (the test) in the strongest words ever", he also noted.
North Korea's recent missile launch over Japan was billed as preparation for a potential strike on Guam.
"This latest action by North Korea is reckless and poses an unacceptable further threat to the global community", May said in an emailed statement.