North Korea's military warned Sunday that it will retaliate if an upcoming South Korean firing drill violates the North's territorial waters.

A notice carried by the North's official Korean Central News Agency warned residents of five islands near the disputed border in the Yellow Sea to evacuate before 9 AM Monday morning. An announcer on a radio broadcast from Pyongyang said there will be an immediate and merciless counter-attack if even a “single column of water” is monitored in North Korean waters during the drill.

South Korea regularly conducts artillery exercises from front-line islands near the disputed border off the west coast of the Korean Peninsula. Such a drill triggered a North Korean artillery bombardment in November of 2010 that killed four South Koreans on the island of Yeonpyeong.

Seoul's semi-official Yonhap news agency cited an unnamed official of the joint chiefs of staff as saying South Korea and the United States will proceed with a live-fire anti-submarine drill Monday despite the warning.

Analysts and U.S. military officers contacted by VOA News say the evacuation advisory is unusual, but that threats of retaliation against South Korean military drills are common and not necessarily cause for any undue alarm.