NATO acknowledged Tuesday that it had lost contact with one of its surveillance drone helicopters, as Libyan state television broadcast pictures of what it said was an alliance attack helicopter that had been shot down.

Libyan television said the images were of an Apache attack helicopter. A NATO spokesman said an “unmanned autonomous helicopter drone” lost radio contact at 9:20 a.m. local time. He did not say whether it had crashed or it had been shot down.

“We are currently looking into the reasons behind this incident,” said Wing Commander Mike Bracken, the spokesman. He said that no Apache helicopters had been lost in the conflict in Libya.

State television said the helicopter had been downed near Zlitan, in the vicinity of the rebel-held city of Misurata. It broadcast images of a nearly totally wrecked small gray aircraft with a red rotor and English-language markings.

NATO deployed attack helicopters to the Libyan operation in late May and said it used them for the first time early this month. NATO said last week that it had used attack helicopters near Zlitan to destroy an anti-aircraft machine gun and three military vehicles. It has also said it is using drones to do extensive surveillance of Libyan government forces.

A U.S. jet crashed near the rebels’ de facto capital of Benghazi in mid-March, but NATO said the drone helicopter was the first aircraft it had lost since it took over Libyan operations at the end of that month.

It is the latest setback for the mission over the past several days. Over the weekend, the alliance said that it had inadvertently struck rebel fighters and that a weapons system malfunction had led to a bomb hitting a residence in Tripoli.

The Libyan government said at least nine were killed in the Tripoli incident. It said Monday that an airstrike had killed 15 civilians west of Tripoli, including several children, and reporters were taken by government minders to a hospital where they saw several charred bodies and the corpses of two children.

NATO said that it had hit a command and control center, and that it was impossible for journalists to verify that the bodies had come from the bombing.