‘The US is ready to launch a pre-emptive strike against North Korea if Pyongyang presses ahead with another round of nuclear weapons tests, it has been reported.

Citing intelligence sources, NBC claimed that the US would be willing to use conventional weapons.

In recent weeks evidence of increased activity at its nuclear test sites has sparked fears that the North may be about to have its sixth nuclear test since 2006 at the weekend.

The threat of another American show of strength emerged as Washington confirmed that the US had dropped the biggest ever non-nuclear bomb in its history on an Islamic State tunnel in eastern Afghanistan.

Tension between Washington and Pyongyang have risen in recent days with the US navy strike group being ordered to move to the western Pacific Ocean.’

Read more: US ‘may launch strike’ if North Korea goes through with nuclear weapons test – reports