German Chancellor Angela Merkel and French President Emmanuel Macron have responded to North Korea's claims it has successfully tested a powerful hydrogen bomb.
Merkel and Macron condemned the latest nuclear test, stating it is a “new dimension of provocation”.
The German government said in a statement that Merkel and Macron agreed North Korea was violating international law and that the international community must react decisively.
“In addition to the United Nations Security Council, the European Union also has to act now. The Chancellor and the President expressed their support for a tightening of EU sanctions against North Korea,” the statement said.
Pyongyang said it had tested a hydrogen bomb, a device much more powerful than an atomic bomb that could be loaded on to a long-range missile, hours after seismologists detected an earth tremor.
In an announcement on state TV, North Korea said it had developed an advanced weapon of “great destructive power”.
The tremors caused were at least ten times more powerful than the last time North Korea detonated an atomic bomb one year ago, Japan’s meteorological agency said.
A 6.3-magnitude earthquake was detected in the country shortly before 7am BST on Sunday, 75km (45 miles) north-northwest of Kimchaek, the location of previous tests.
The test represents a challenge to US President Donald Trump, who spoke to Japanese Prime Minister Shinzo Abe hours earlier about the nuclear crisis in the region.
“It is absolutely unacceptable if North Korea did force another nuclear test, and we must protest strongly,” Mr Abe said.
Analysts fear the test signifies a significant step forward in the state’s quest for a nuclear missile capable of striking the US.
South Korea’s President will chair a National Security Council meeting. It said North Korea’s latest nuclear test should be met with the “strongest possible” response, including UN security council sanctions to “isolate” the country.
Earlier this year, the state tested two intercontinental ballistic missiles in July. Last month, it fired a missile believed to be a Hwasong-12 over northern Japan.
Earlier on Sunday, the North Korea government released photos showing Kim Jong-un looking at a silver device that was allegedly the hydrogen bomb, although this has not been verified.
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