The screech of incoming fire followed by an explosion resounds across forested hillsides near the border between North and South Korea.

Battalion commander Rob Kimmel of the U.S. 2nd Armored Brigade Combat Team scanned the village at the base of a mountain for the tell-tale smoke.

"That's enemy fire trying to attack R.O.K. forces located there," says Kimmel — referring to South Korea by its official name, the Republic of Korea.