A U.S. marine took his own life by putting a bullet through his head on Sunday morning near the restive city of Fallujah.

"Early in the morning, a marine took the pistol of an Iraqi policeman in the police station of Amriyah town just south of Fallujah, and put a bullet in his head," the source told Xinhua on condition of anonymity.

"The soldier uttered words saying he was sad and miserable," the source said.

The U.S. troops kept the policeman who gave the marine the pistol for several hours, but released him later, he added.