Wrapping up four days of joint drills in the West Sea on Wednesday, the South Korean and U.S. militaries are reportedly discussing follow-up drills in late December in preparation for further provocations by North Korea.

A military source said they are "talking about ways to stage one more round of joint maritime exercises after mid-December, with both the East and West Seas in mind."

Marines stand guard on Yeonpyeong Island on Wednesday, the last day of South Korea-U.S. joint drills in the West Sea.

An official with the Joint Chiefs of Staff said, "The two countries had planned to stage several rounds of joint exercises this year in response to the North's attack on the Navy corvette Cheonan in March. But the need has arisen for more rounds of joint drills in the wake of the North's latest artillery attack. We're planning another round of joint drills before the end of this year, but it could be delayed until early next year."

Aegis destroyers and nuclear-powered attack submarines of the Seventh U.S. Fleet are expected to participate in the follow-up drills instead of the U.S. aircraft carrier George Washington. The joint drills that started last Sunday came to an end on Wednesday afternoon.

Meanwhile, the Marines are considering maritime fire drills on Yeonpyeong and the other four West Sea islands next week. Their original plan was to carry them out on Tuesday.