The United States warned it could launch a "massive military response" to any threats from North Korea following Pyongyang's provocative detonation of what it claimed was a miniaturized hydrogen bomb.
Defense Secretary Jim Mattis spoke out on Sunday after North Korea carried out an unexpectedly strong nuclear test, said to exceed in power the 1945 atomic bombing of Hiroshima.
President Donald Trump called an emergency meeting of his national security advisers and had his second telephone call of the weekend with Japanese Prime Minister Shinzo Abe, but did not talk to South Korea's Moon Jae-In -- instead accusing Seoul of "appeasement".
He threatened drastic economic sanctions, including "stopping all trade with any country doing business with North Korea."
US monitors measured a powerful 6.3-magnitude earthquake near the North's main testing site on Sunday, felt in parts of China and Russia, with an aftershock possibly caused by a rock collapse.
The North -- which in July carried out two intercontinental ballistic missile (ICBM) launches that apparently brought much of the US mainland into range -- hailed its test of what it described as a hydrogen bomb designed for a rocket as "a perfect success."
Mattis told reporters: "Any threat to the United States or its territories, including Guam, or our allies will be met with a massive military response, a response both effective and overwhelming.
"We are not looking to the total annihilation of a country, namely North Korea," he added, but warned: "We have many options to do so."
Pyongyang residents celebrated as a jubilant television newsreader hailed the "unprecedentedly large" blast which she said had moved the country closer to "the final goal of completing the state nuclear force."
It prompted an international chorus of condemnation, including from both the North's key ally China and Russia, which also has links with Pyongyang.
UN Secretary General Antonio Guterres condemned the test as "profoundly destabilizing," while the Security Council will hold an emergency meeting on Monday.
North Korea has conducted a major Nuclear Test. Their words and actions continue to be very hostile and dangerous to the United States.....Donald J. Trump (@realDonaldTrump) September 3, 2017
South Korean President Moon Jae-In, who advocates engagement as well as penalties to bring Pyongyang to the negotiating table, called for new United Nations sanctions to "completely isolate North Korea."
On Monday Seoul carried out a live-fire exercise in the East Sea, its name for the Sea of Japan, using a volley of missiles to simulate an attack on the North's nuclear site.
South Korea is finding, as I have told them, that their talk of appeasement with North Korea will not work, they only understand one thing!Donald J. Trump (@realDonaldTrump) September 3, 2017
But Trump criticised the US treaty ally on Twitter, saying: "South Korea is finding, as I have told them, that their talk of appeasement with North Korea will not work, they only understand one thing!"
In a statement, the presidential Blue House retorted: "Korea is a country that experienced a fratricidal war."
It "will continue to push for the denuclearization of the Korean Peninsula through peaceful means working together with our allies", it added.
'Cut off North Korea'
Hours before the test, the North released images of Kim at his country's Nuclear Weapons Institute, inspecting the device it called a "thermonuclear weapon with super explosive power" entirely made "by our own efforts and technology," according to the Korean Central News Agency.
A series of US and United Nations-backed sanctions seem to have had little effect on Pyongyang.
US Treasury Secretary Steven Mnuchin said Sunday his department was preparing potent new measures that would "cut off North Korea economically."
When its founding father Kim il-Sung dies in July 1994, North Korea is an isolated, impoverished and relatively insignificant country on the world stage. His son Kim Jong-il becomes the reclusive state’s “Eternal President”. © KNS, AFP
Kim Jong-il, pictured here in September 1998, spearheads North Korea’s nuclear weapons programme, persuaded that it is the only guarantee of his regime’s survival. © AFP
A picture of the Yongbyon-1 nuclear facility, taken in 1992. The site’s reactor is temporarily stopped in 1994 following an international accord aimed at freezing the country’s nuclear programme. © HO, IAEA, AFP
Kim Jong-il hosts US Secretary of State Madeleine Albright for talks in Pyongyang in October 2000. But the negotiations collapse after North Korea demands $1 billion a year in return for halting missile exports. © David Guttenfelder, Pool, AFP
More than a million people gather in Pyongyang on January 11, 2003, to celebrate the country’s withdrawal from the Nuclear Non-Proliferation Treaty. © Xinhua, AFP
North Korea’s very first nuclear test is announced on state TV on October 9, 2006. The jubilant presenter will soon become a familiar face for viewers around the world.
The death of “Dear Leader” Kim Jong-il in December 2011 leads to an outpouring of grief across North Korea. Abroad, Kim’s passing prompts much speculation as to the reclusive state’s future course under his successor. © KNS, KCNA, AFP
The world discovers Kim Jong-il’s baby-faced son and successor, Kim Jong-un. Having studied in Europe, the new Kim seems at first less isolationist than previous Kims. But hopes of a thaw in relations soon give way to disillusion. © AFP
Kim Jong-un is pictured inspecting a military base and observing missile tests on May 22, 2017. His rise to power coincides with a further acceleration of Pyongyang’s nuclear programme, and a brazen dismissal of international condemnation. © AFP
Relations with the US hit a new low after Donald Trump's election. On August 8, 2017, Trump threatens to unleash “fire and fury like the world has never seen” if North Korea continues its weapons programme. A month later, Pyongyang carries out a sixth nuclear test. © Jung Yeon-Je, AFP
The measures would ensure that "anybody that wants to do trade or business with them will be prevented from doing trade or business with us," he said on "Fox News Sunday."
While the United States has virtually no trade with the North, the burden of sanctions such as Mnuchin described would fall heavily on China, which buys about 90 percent of North Korean exports.
Tremor felt in China, Russia
South Korean experts said the tremor near the North's main test site was five to six times stronger than that from a 10-kiloton test a year ago.
As well as July's landmark ICBM tests, Pyongyang last week fired a missile over Japan.
Trump has warned Pyongyang that it faces "fire and fury" and that Washington's weapons are "locked and loaded."
But the North has huge artillery forces within range of Seoul, a city of 10 million people, and could inflict mass casualties in retaliation to any strike.
"There are no realistic military options in terms of striking North Korea, because doing so would likely spark a full-scale war," Mark Fitzpatrick, executive director for America of the International Institute for Strategic Studies, told AFP.
Date created : 2017-09-03