Donald Trump has condemned North Korea’s latest nuclear test as the biggest foreign policy challenge faced by his administration deepened overnight.

“North Korea has conducted a major nuclear test,” the president tweeted on Sunday morning. “Their words and actions continue to be very hostile and dangerous to the United States.

“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 also accused South Korea of favouring a policy of “appeasement”, telling Seoul that “will not work” because the North Koreans “only understand one thing!”

In a surprise announcement on state TV, North Korea said it had tested a powerful hydrogen bomb that could be loaded on to an intercontinental ballistic missile, in a move that is expected to increase pressure on Trump to defuse the growing nuclear crisis on the Korean peninsula.

Pyongyang said the test, its sixth since 2006, had been a “complete success” and involved a two-stage thermonuclear weapon of unprecedentedstrength.

There has been no independent verification of North Korea’s claims that it has achieved a key goal in its nuclear programme – the ability to miniaturise a warhead so that it can fit on a long-distance missile.

The regime has earlier released footage of what it said was a hydrogen bomb that would be loaded on to a new ICBM.

The TV announcement, which was accompanied by patriotic music and images of North Korean landscape and military hardware, said the test had been ordered by the country’s leader, Kim Jong-un.

The explosion caused by a 6.3-magnitude earthquake felt in Yanji, China, about six miles (10km) from North Korea’s Punggye-ri nuclear test site in the north-east of the country.

South Korea’s meteorological administration estimated the blast yield at between 50 to 60 kilotons, or five to six times more powerful than North Korea’s fifth test in September last year.

Kim Young-woo, the head of South Korea’s parliamentary defence committee said later that the yield was as high as 100 kilotons. One kiloton is equivalent to 1,000 tons of TNT.

The previous nuclear blast in North Korea is estimated by experts to have been about 10 kilotons.

Sunday’s test, the first since Trump took office in January, offers further evidence that North Korea is moving perilously close to developing a nuclear warhead capable of being fitted on to an ICBM that can strike the US mainland.

Since it conducted its first nuclear test just over a decade ago, the regime has strived to refine the design and reliability of it weapons, as well as increasing their yield.

Hydrogen bombs are far more powerful than the atomic weapons Pyongyang is believed to have tested so far.

China’s foreign ministry said in a statement: “The Democratic People’s Republic of Korea has once again conducted a nuclear test in spite of widespread opposition from the international community. The Chinese government resolutely opposes and strongly condemns it.”

Before taking office, Trump declared North Korea would not be allowed to develop an ICBM capable of reaching the US mainland under his presidency.

After Pyongyang carried out two successful ICBM tests in July, Trump warned it would face “fire and fury like the world has never seen” if it made any further threats.

North Korea has since threatened to fire a salvo of missiles into the seas around the US Pacific territory of Guam, and fired a ballistic missile over Japanese territory for the firs time, ending US hopes that Trump’s threats had cowed Pyongyang into a pause in missile tests and a possible opening for talks.

In contrast to Trump, the US secretaries of defence and state, James Mattis and Rex Tillerson, have both emphasised that the US is relying on diplomacy and economic pressure in its approach to Pyongyang.

Complicating matters, Trump seems to be considering asking aides to prepare for US withdrawal from a free trade agreement with South Korea, it was reported on Saturday. Via Guardian

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