South Korean defence minister resigns

South Korea's defence minister has resigned amid criticism over his handling of North Korea's shelling of an island near their disputed maritime border.



President Lee Myung-bak is expected to name a successor today.



Tuesday's attack left two South Korean civilians and two marines dead, and sent regional tensions soaring.



South Korea has increased troops on Yeonpyeong and other nearby islands, and announced more rigorous rules of engagement for future incidents.