NATO denied a Libyan government claim that one of its Apache helicopters was shot down, but did say contact was lost with an unmanned drone helicopter, DPA reported.
Libyan state television aired footage of what it claimed was a NATO Apache helicopter that had been shot down in Zleitan, 180 kilometres east of the capital Tripoli.
However, the alliance "received reports that an unmanned autonomous helicopter drone, used by NATO forces, lost radar contact with the command centre," a NATO spokesperson in Brussels said.
"This drone helicopter was performing intelligence, surveillance and reconnaissance over Libya to monitor pro-Gaddafi forces threatening the civilian population," he added.
NATO has been carrying out airstrikes targeting Moamer Gaddafi's forces and aiming to protect civilians since late March.