From the Washington Post:
After midnight on a bare stretch of highway near this ramshackle town last week, Staff Sgt. Jason Hoover saw what looked like a fishing line strung across the road and ordered his Humvee to a screeching halt.
The cord was connected to an old, Russian artillery shell half-buried in the earthen shoulder and rigged to activate with a firm tug. Hoover traced its path nearly a half-mile though a plowed field, over another highway, and across a canal, where he found four Iraqi infrastructure policemen who were supposed to be guarding an oil pipeline. They said they had no idea what the cord was doing there.
Here.