South Korean officials said on Monday that they had gathered intelligence indicating that the North was preparing to demolish its half of roads that connect the two countries.

"They have installed screens on the road and are working behind those screens, preparing to blow up the roads," Lee Sung Joon, a spokesperson for South Korea's Joint Chiefs of Staff, told reporters.

He said the operation could take place as soon as Monday.

The move follows weeks of soaring tensions on the Korean peninsula. North Korea has accused South Korea of using drones to drop propaganda leaflets over its territory three times, and threatened to respond with force if it happens again.

North 'fully ready to open fire'

North Korea's Defense Ministry said in a Sunday statement that it had positioned several army units near the border and was "getting fully ready to open fire" and that South Korea would "turn into piles of ash" if it attacked.

Koo Byoungsam of South Korea's Unification Ministry said the move was likely motivated by a desire to strengthen unity within North Korea by concentrating on a common enemy.

Pyongyang often uses warlike rhetoric in the build-up to missile tests that the UN has banned them from carrying out. Experts say an all-out attack is unlikely, given the superior firepower and numbers from South Korea and its ally, the US.

However, destroying the cross-border roads would mark a major blow to decades of work toward a peaceful unification of the two countries.

Last January, North Korean dictator Kim Jong Un amended the constitution to remove language about reunification and declared the South his "invariable principal enemy."

es/zc (AP, Reuters)