Libyan state television repeatedly broadcast images of what appeared to be aircraft wreckage, including shots of a red rotor and close-ups of markings in English.

It quoted an unnamed Libyan military official saying a NATO Apache attack helicopter crashed in Zlitan, about 135 kilometers east of the capital Tripoli. The report claimed it was the fifth Apache that had been downed — a charge NATO denied.

Wing Cmdr. Mike Bracken, an alliance spokesman, said NATO instead lost radar contact with an unmanned helicopter drone Tuesday morning along the coast in central Libya, and is investigating the incident. He said the drone was performing an intelligence, surveillance and reconnaissance mission.

“This is the first piece of hardware that I am aware of that has been lost” since NATO’s air campaign began, Bracken said. A US F-15E jet crashed near the rebel stronghold of Benghazi in March before NATO assumed command of the international intervention in Libya.

A coalition including France, Britain and the United States began striking Qaddafi’s forces under a United Nations resolution to protect civilians on March 19. NATO assumed control of the air campaign over Libya on March 31.

At least one distant explosion rumbled across Tripoli Tuesday as warplanes roared overhead. It wasn’t immediately clear what was hit or whether there were casualties.

What started as a peaceful uprising inside the country against Qaddafi and his more than four-decade rule has devolved into a civil war. Rebels control the eastern third of the country and pockets in the west, and are trying to push their front line forward from their western stronghold of Misrata toward the nearby city of Zlitan.

Qaddafi’s forces have countered with barrages of rockets and mortars, and the fighting on the front lines in Dafniya, some 15 miles (25 kilometers) west of Misrata, has been fierce in recent weeks.

Rockets fired by Libyan government troops have been hitting closer to Misrata this week. On Monday, a rocket struck the front yard of a home in the area of Ruweislat in Misrata, killing a 14-year old boy and burning his mother and brother, according to the boy’s uncle, Taher Abu Sheiba.

In London, British Prime Minister David Cameron rebuked military officers who have questioned whether the UK can continue its key role in NATO’s Libya campaign over the long term.

The country’s top naval officer last week warned that British forces might not be able to respond quickly to new threats if Libyan operations extend beyond September. On Tuesday, concerns surfaced from Britain’s head of air force combat operations, who said the air force was running short on pilots and ground crew staff because so many personnel were either deployed or resting following a period of combat duty.