The shots were fired from the Yonan County in South Hwanghae Province at around 12:30 p.m. local time (03:30 GMT). The shells landed in the western buffer zone set under the 2018 inter-Korean military agreement. Seoul has repeatedly warned Pyongyang that artillery shelling within buffer zones in the Sea of Japan and the Yellow Sea is a violation of the agreement.
"We strongly warn that artillery shelling in the maritime buffer zone is a clear violation of the 9.19 Military Agreement and this ongoing provocation by North Korea is an act that undermines peace and stability not only on the Korean Peninsula, but also in the international community. We urge an immediate ceasefire," the South Korean military said in a statement.
According to South Korean news agency Yonhap, North Korea fired up to 250 artillery shots into waters off its east and west coasts from around 10 p.m. (13:00 GMT) on Tuesday.
North Korea has carried out eight test launches since September 25 and over 25 since the beginning of 2022. Pyongyang has emphasized that its test launches are being carried out in response to the refusal of the US and South Korea to stop joint military drills, which Pyongyang believes threaten regional stability.