The South Korean military says the buffer zones created under a 2018 military agreement with North Korea "no longer exist."

Under the pact, Seoul and Pyongyang agreed to avoid firing artillery shells near the de-facto border between the two Koreas to prevent accidental clashes.

But South Korea's military said North Korean forces fired artillery into the Yellow Sea, west of the Korean Peninsula, starting Friday and continuing on the next two days. The shells were fired near islands belonging to South Korea.

At a news conference on Monday, the South Korean Joint Chiefs of Staff accused the North of repeatedly violating the agreement. South Korea's military said it will resume shelling and other drills in the buffer zones.

Last November, South Korea partially suspended the agreement after the North launched a military satellite. This prompted the North Korean defense ministry to announce that its military is no longer bound by the deal.