North Korean leader, Kim Jong Un warned that his government will not hesitate to launch a nuclear attack on the US if 'provoked with nukes.'

He made the warning after a meeting between South Korea and the United States was held last week in Washington, where they discussed nuclear deterrence in the event of conflict with the North.

The meeting's agenda included 'nuclear and strategic planning', and the allies reiterated that any nuclear attack by Pyongyang on the United States or South Korea would result at the end of the North Korean regime.

But Kim reportedly told his military's missile bureau 'not to hesitate (launching) even a nuclear attack when the enemy provokes it with nukes,' Pyongyang's official Korean Central News Agency said Thursday.

Washington, Seoul, and Tokyo released a statement shortly afterwards, urging the nuclear-armed country to 'stop conducting further provocations and accept our call for engaging in substantive dialogue without preconditions'.

The three countries have ramped up defence cooperation in the face of a record-breaking series of weapons tests by Pyongyang this year, and on Tuesday activated a system to share real-time data on North Korean missile launches.

On Monday, the North launched its most powerful intercontinental ballistic missile, the Hwasong-18, later describing it as 'a warning counter-measure' against what it described as persistent acts of 'military threat' by Washington and its allies.

It came after a US nuclear-powered submarine arrived in the South Korean port city of Busan last week, and on Wednesday, Washington flew its long-range bombers in drills with Seoul and Tokyo.