US warns North Korea of 'massive military response' after nuclear test
US Defence Secretary Jim Mattis has reacted to North Korea's latest nuclear test by saying threats to the United States and its allies "will be met with a massive military response".
Mr Mattis spoke at the White House following a meeting with President Donald Trump and national security advisers. He said any response will be "both effective and overwhelming".
Mr Mattis said the United States is "not looking to the total annihilation" of North Korea, but added "we have many options to do so".
North Korea claimed "perfect success" in an underground test of what it called a hydrogen bomb - potentially vastly more destructive than an atomic bomb.
It was the North's sixth nuclear test since 2006, but the first since Mr Trump took office in January.
The United Nations Security Council will hold an emergency meeting in response to North Korea's most powerful nuclear test.
The meeting on Monday comes at the request of the UK, US, Japan, France and South Korea, comes after Kim Jong Un's regime carried out its sixth test of a nuclear device.
In the UK Foreign Secretary Boris Johnson cautioned against a military strike, because North Korea already had the ability to "vaporise" large parts of the population of South Korea even without nuclear weapons.
Prime Minister Theresa May said Pyongyang's actions posed an "unacceptable further threat to the international community" and urged world leaders to increase pressure on the regime.
The test blast 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.
Mrs May reiterated the call for "tougher action, including increasing the pace of implementation of existing sanctions and looking urgently in the UN Security Council at new measures" she had made alongside Japanese Prime Minister Shinzo Abe during her visit last week.
She said: "This is now even more pressing. The international community has universally condemned this test and must come together to continue to increase the pressure on North Korea's leaders to stop their destabilising actions."
Mr Trump branded North Korea "a rogue nation" and indicated that he was considering a trade boycott of nations that dealt with North Korea - widely viewed as a reference to China, although commentators questioned how the US would be able to take such a step.
The Foreign Secretary played down the prospect of military action although he acknowledged all options remained on the table.
Mr Johnson said: "There is no question that this is another provocation, it is reckless, what they are doing is, they seem to be moving closer towards a hydrogen bomb which, if fitted to a successful missile, would unquestionably present a new order of threat."
Arguing for a diplomatic solution he said: "It's certainly our view that none of the military options are good. It is of course right to say that all options are on the table, but we really don't see an easy military solution."
The Chinese government "expressed firm opposition and strong condemnation" and urged North Korea to "stop taking erroneous actions that deteriorate the situation".
But Mr Johnson urged Beijing to go further in putting economic pressure on its neighbour.
He said: "Our message to the Chinese is, and we are working ever more closely with them, we think there is more scope for you, the Chinese, to put economic pressure on the North Koreans.
"It has worked, we have seen signs in the last six months of Chinese pressure actually changing the approach of North Koreans - let's see if we can do it again."
European Council president Donald Tusk said: "The EU stands ready to sharpen its policy of sanctions and invites North Korea to restart dialogue on its programmes without condition.
"We call on the UN Security Council to adopt further UN sanctions and show stronger resolve to achieve a peaceful denuclearisation of the Korean peninsula. The stakes are getting too high."
The artificial earthquake triggered by the North Korean test was several times stronger than from previous blasts and reportedly shook buildings in China and Russia.
The test was carried out at 12.29pm local time at the Punggye-ri site where North Korea has conducted nearly all of its past nuclear tests.
Officials in Seoul put the magnitude of the quake at 5.7 while the US Geological Survey said it was 6.3.