North Korea is reported to have augmented its frontline corps with six light infantry units.

A military source said that three military corps in the North have each added two more light infantry units.

It went on to say that, an infantry unit of five- or six-thousand lightly armed troops can infiltrate South Korea, identify targets and carry out operations to cause destruction and confusion.

However, the source said it was hard to tell whether the changes posed a critical threat to South Korea.