Kim Jong-un is plotting another ballistic test it has emerged this morning after Seoul simulated its own missile raid on the North in the wake of the dictator's hydrogen bomb test.

South Korea launched a spectacular rocket launch exercise hitting 'designated targets in the East Sea' last night in response to Pyongyang's provocative detonation.

The US warned it could launch a 'massive military response' to any threats from North Korea after the rogue state announced it had carried out its most powerful nuclear test yet.

Earlier, when asked if he planned to attack Pyongyang, Donald Trump replied, 'We'll see', and said he was holding a meeting with his military leaders. Mr Trump also tweeted that talk of appeasement was pointless because North Korea 'only understand one thing', as the state promised further tests.

His hard-line rhetoric was prompted by Pyongyang's announcement that it had successfully tested a weapon up to ten times more powerful than the Hiroshima bomb that could kill millions of people. 

But this morning South Korea announced it had detected signs Kim Jong-un was preparing to carry out yet another launch - possibly of an intercontinental ballistic missile. Seoul and the US said this morning it will deploy more anti-missile defences despite a The Terminal High-Altitude Area Defense (THAAD) system already being installed in the South. Last night, the South's military conducted a live-fire exercise simulating an attack on the north's nuclear site, hitting 'designated targets in the East Sea', the report added, quoting the Joint Chiefs of Staff.  

Pictures showed South Korean short-range Hyunmoo ballistic missiles roaring into the sky in the pale light of dawn from a launch site on the country's east coast. Authorities released video showing South Korean F-15K fighter jets firing air-to-ground missiles.

The weapons accurately hit their targets in the East Sea - the Korean name for the Sea of Japan - the South's Joint Chiefs of Staff said in a statement.

The exercise 'was carried out as a strong warning' to the North for conducting its sixth nuclear test, it added. 

The training involved long-range air-to-surface missiles and ballistic missiles.

The country is also preparing fresh military drills with its ally the United States in response to North Korea's sixth and most powerful nuclear test a day earlier.