North Korea's Kim Jong-un
Kim Jong-un exhorts soldiers to prepare for 'looming conflict with US' Reuters

North Korean leader Kim Jong-un has urged the country's soldiers to prepare for battle with the US as President Barack Obama is set to wrap up his two-day visit to Seoul amid simmering tensions in the Korean peninsula.

On a visit to supervise North Korean soldiers, Kim said that nothing is more important for the country's troops than war preparation.

The state-run mouthpiece Korean Central News Agency said: "Dear Supreme Commander Kim Jong-Un said nothing is more important than preparing for combat now, in the face of a looming conflict with the United States."

Kim usually visits the country's troops and oversees the military installations in order to keep a close watch on their activities. The visits are also regularly reported in Pyongyang's mouthpieces; Kim normally heaps praise on the troops rather than being critical.

On this occasion, however, Kim criticised the soldiers for what he saw as lack of combat readiness during the recent face-off with South Korean forces during a naval drill.

Kim said: "The minds of the commanding officers of this sub-unit and relevant unit seem to be away from the battlefield. Of course, they might do sideline jobs for improving service personnel's living conditions and do their bit in building a rich and powerful nation."

"However, they should always give priority to combat preparations."

The latest bout of belligerence comes alongside Obama's trip to North Korea's arch rival South Korea.

Obama, who is currently on the second leg of his Asia tour, in a series of stinging remarks against Pyongyang, said: "Anybody can make threats. That does not make you strong. Those things don't come through force, they have to be earned. We don't hesitate to use our military might to defend our allies and our way of life."

Tensions have increased in the last few days following reports that North Korea stepped up activity at its nuclear test site fuelling suspicion that the reclusive nation is preparing for a fourth nuclear test.