South Korea on Highest Alert

On Monday, South Korean forces went to their highest alert level and has begun mobilizing troops north.

They are responding to reports that North Korean self propelled artillery and other troops have moved south towards the border.

North Korea has promised a military response if a planned leaflet dropping isn't stopped by the South.

Defectors from the North are working with humans rights group to use balloons to drop thousands of leaflets on the North through Monday.

The leaflets will contain messages critical of the North's government and encourage people to defect to the South.