The firing by North Korea caused no civilian or military damage in the South, South Korea's military said in a news briefing.

"This is an act of provocation that escalates tension and threatens peace on the Korean peninsula," a spokesman for the South Korean Joint Chiefs of Staff said.

The North Korean artillery shells all landed on the northern side of the sea border (Northern Limit Line) , South Korean military spokesman Lee Sung-joon said in a news briefing, adding that the South Korean military has been monitoring the North's moves along its shores with the cooperation of the US military.