BAGHDAD, Iraq — An unmanned Air Force Predator fired a Hellfire missile at three Iraqis planting a roadside bomb near Balad Air Base north of Baghdad, killing all three, the U.S. military said Wednesday.

Cameras on the Predator sent back live pictures of the three insurgents for about half an hour Tuesday night as they dug a hole in the road, placed the explosive and ran triggering wires to a ditch near the road, according to a Central Command statement.

“This strike should send a message to our enemies that we’re watching you, and we will take action against you any time, day or night, if you continue to stand in the way of progress in Iraq,” Brig. Gen. Frank Gorenc, commander of the 332nd Air Expeditionary Wing at Balad, said in the statement.

Balad, 40 miles north of Baghdad, has become the logistics hub for all U.S. military operations in Iraq. It was the former Iraqi air force academy.