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, more powerful than the bomb that levelled Hiroshima in 1945.

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.”

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.”

The White House said the US was committed to “defending our homeland, territories, and allies using the full range of diplomatic, conventional, and nuclear capabilities at our disposal.”

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 allies, China and Russia.

UN Secretary General Antonio Guterres condemned the test as “profoundly destabilizing”. The Security Council will hold an emergency meeting on Monday.

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.”