SEOUL, Dec. 26 (Xinhua) -- South Korean military will continue its marine gunnery exercises in 23 sites around the country in the last week of this year.

Korea Hydrographic and Oceanographic Administration (KHOA) on Sunday issued a navigation warning on its website to warn civilian ship to keep a sharp lookout and avoid the 23 areas designated for the drills during the period from Monday to Friday.

According to the website, the drill will be staged in 12 sites in waters off the west coast, six sites off the south coast and five sites off east coast respectively, but no drills are scheduled near the contentious sea border called Northern Limit Line (NLL).

Seoul's Ministry of National Defense said this week's drills will be part of the routine exercises of the military.

The KHOA has released as many as 390 navigation warnings this year, most of them were associated with Navy's drills.