A homemade bomb (search) planted on a road exploded Saturday as a U.S. Army convoy passed by, killing three soldiers, the U.S. military said.

A military spokesman said an improvised bomb blew up about 25 miles southwest of Kirkuk (search), near a convoy of the 4th Infantry Division. The spokesman said he had no other details.

Kirkuk, a major oil producing area, is about 60 miles north of Tikrit (search) where the 4th Infantry Division is based.