North Korea could be preparing new missile launch: Seoul

The South and the United States will deploy more of the Terminal High-Altitude Area Defence (THAAD) missile launchers that have infuriated Beijing, the defence ministry said.

The announcement came after Seoul fired an early-morning volley of ballistic missiles in an exercise simulating an attack on the North's nuclear test site.

Pictures showed South Korean short-range Hyunmoo missiles roaring into the sky in the pale light of dawn from a launch site on the east coast.

Pyongyang said the device it detonated Sunday was a hydrogen bomb - far more powerful than the fission-based devices it is believed to have previously tested - and small enough to fit into a missile.

The blast threw down a new gauntlet to President Donald Trump, after the North in July twice tested an intercontinental ballistic missile (ICBM) that appeared to bring much of the US mainland into range, and threatened to send a salvo of missiles towards the US territory of Guam.

South Korean defence ministry officials estimated its strength at 50 kilotons - five times the size of the North's previous nuclear test.

They did not confirm whether it was a hydrogen bomb, saying only that "a variety of nuclear material" had been used.

But Defence Minister Song Young-Moo said Seoul believed Pyongyang had succeeded in miniaturising its nuclear weapons to fit into an ICBM.

The South had requested the US deploy strategic assets such as aircraft carriers and bombers to the peninsula, he said, but denied reports Seoul was seeking the return of US tactical nuclear weapons.

Signs that North Korea was "preparing for another ballistic missile launch have consistently been detected since Sunday's test", the ministry said.

It did not indicate when a launch might take place, but said it could involve an ICBM being fired into the Pacific Ocean to raise pressure on Washington further.

After yesterday's test the United States warned it could launch a "massive military response" to threats from North Korea that would be "both effective and overwhelming".

"We are not looking to the total annihilation of a country, namely North Korea," Defence Secretary Jim Mattis said, but warned: "We have many options to do so."

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 he did not talk to South Korea's Moon Jae-In for more than 24 hours - instead accusing Seoul of "appeasement", raising jitters in Seoul about the two countries' decades-old alliance.

Moon, 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."