South Korea fired warning shots at North Korean soldiers that briefly crossed the heavily fortified border earlier this week, Seoul said Saturday after Pyongyang accused it of risking

South Korea and North Korea traded accusations after Seoul fired warning shots when Northern troops briefly crossed the border, with Pyongyang denouncing it as a 'serious provocation'.

The drills, which will kick off next week, are a "direct military provocation" against North Korea, Pyongyang said.