On Sunday North Korea carried out its most powerful nuclear test to date.
North Korea’s state media announced that the country had detonated a hydrogen bomb with “perfect success”.
A 6.3 magnitude earthquake detected near a weapons test site in the country’s northeast indicates a 100 kiloton explosion.
South Korean scientists say the ‘explosion’ was far more powerful than previous tremors recorded after Pyongyang’s tests.
Sky News reports: Pyongyang’s only major ally, China, said it strongly condemned the detonation.
Earlier, Japan confirmed its near neighbour had conducted a sixth nuclear test.
The country’s meteorological agency said the resulting tremors were at least 10 times as powerful as North Korea’s previous nuclear test, last September.
Experts estimated that blast to have been around 10 kilotons.
It means this latest device was about five times larger than the bomb dropped on the Japanese city of Nagasaki in World War II.
The US Geological Survey said a magnitude 6.3 tremor struck near a weapons test site in the northeast of North Korea.
A second tremor measuring 4.6 was also detected, South Korea’s Yonhap news agency said.
Japan’s foreign minister, Taro Kono, described the new explosion as “extremely unforgivable”.
The Tokyo government has registered a protest with the North Korean embassy in Beijing, he said.
Hours earlier, Japanese Prime Minister Shinzo Abe spoke to US President Donald Trump on the phone about the “escalating” situation.
South Korea has called for the “strongest possible” response, including new sanctions from the UN Security Council to “completely isolate” its northern neighbour.
Seoul’s national security adviser, Chung Eui-yong, said there had been talks with Washington about deploying US strategic military assets to the Korean peninsula.
Sky News’ Asia Correspondent, Katie Stallard, said: “The significant point to take out of all of this is in terms of what response we see from the United States.
“We’ve seen over the last weeks and months increasing rhetoric from both sides, culminating memorably in Donald Trump’s threat of ‘fire and fury’ against Kim Jong Un’s regime if they continued to make threats.
“So the question is, given his previous rhetoric, his previous threats, how Donald Trump plans to respond to this.”
Russian President Vladimir Putin and his Chinese counterpart, Xi Jinping, have said it is important to prevent chaos on the Korean Peninsula and are calling for a diplomatic solution to the crisis, following news of the latest nuclear test.
Putin “called on the international community not to give in to emotions and to take a reasonable and balanced approach”
According to RT: Earlier in the day, the Russian Foreign Ministry condemned the North Korean test, adding that in a situation like this, it is essential “to keep composure and to restrain from any acts, which may lead to further escalation of tensions.”
The test is “another example of Pyongyang’s outright disregard” of UN Security Council resolutions and international law, the ministry said in a statement.
“We cannot but regret the fact the DPRK [North Korea] leadership is creating grave threats to peace and security on the Korean Peninsula and the whole region by its actions, which are aimed at undermining the global non-proliferation regime. The continuation of this line is fraught with grave consequences for the DPRK itself.”
On Sunday, North Korean state media reported that Pyongyang successfully tested a hydrogen bomb which can be mounted on an Intercontinental Ballistic Missile (ICBM). The test followed Pyongyang’s claims that it developed a new, more advanced hydrogen nuke that is small enough to be fitted on an ICBM.