South Korean marines have conducted their final live-fire artillery drills for the year near the disputed maritime border with North Korea, the military announced Tuesday.

The Northwestern Islands Defense Command said the 6th Marine Brigade and the Yeonpyeong Unit completed their “fourth-quarter live-fire training” near the Northern Limit Line (NLL) in the Yellow Sea, describing the drills as “routine and defensive in nature.”

The defense ministry said around 100 rounds from K9 self-propelled howitzers were fired into waters south of the maritime boundary.

The ministry told NK Newsthat the military coordinated with the U.N. Command to notify North Korea