Video shows the drills near the disputed maritime border with South Korea . Pyongyang has stepped up its rhetoric against South Korea 's President Lee Myung-bak and his government since Kim Jong Un took over as North Korean leader last December after the death of his father , longtime leader Kim Jong Il . The drill is part of a series of military exercises that began in March and are expected to continue through September. `` We will turn Seoul into a sea of flames , '' a military deputy commander says .
Video shows the drills near the disputed maritime border with South Korea . The drill is part of a series of military exercises that began in March and are expected to continue through September. `` We will turn Seoul into a sea of flames , '' a military deputy commander says .