South Korea and the United States are apparently putting serious thought to whether they will conduct their joint "Key Resolve” military exercise this year.

A government source said Friday that the two nations are coordinating details of the exercise, which is usually carried out annually from the end of February to early March. The source said this year both countries have a number of variables to consider, including the death of North Korean leader Kim Jong-il and internal changes in the North.

The source said South Korea and the U.S. have yet to come up with a final schedule for the drill, which aims to prepare for potential North Korean provocations or a full-scale war.

The allies are apparently taking into consideration that the North is in a period of mourning and whether its new leadership has stabilized.