North Korea fired artillery shells off its east and west coasts on Tuesday, the South Korean military said.
The North fired some 100 shells into the sea off its west coast around 10 p.m. local time and shot a further 150 rounds off its east coast, the Joint Chiefs of Staff said in a statement on Wednesday.
North Korea's latest military activity came after South Korean troops kicked off their annual Hoguk defense drills on Monday, designed to boost their ability to respond to North Korea's nuclear and missile threats.
The drills, due to end on Saturday, are the latest in a series of military exercises by South Korea in recent weeks, including joint activities with the United States and Japan.