The airstrikes came a day after fierce clashes erupted in the Libyan capital.
The rebels said pro-Gaddafi forces were still shelling the airport and sporadic shooting was reported elsewhere, but the streets of Tripoli were relatively calm today.
The military alliance that NATO warplanes targeted 29 vehicles mounted with weapons near the city, which is 400 kilometres east of the Libyan capital of Tripoli.
Rebels are trying to occupy Sirte but expect fierce resistance from tribesman and towns people loyal to Gaddafi.
The rebel leadership, apparently trying to avoid the bloodshed that occurred in the battle for Tripoli, is working behind the scenes to secure the peaceful surrender of Sirte, officials said.
But the latest NATO airstrikes on loyalist vehicles defending Sirte appeared aimed at paving the way for the rebel advance if a negotiated settlement proves impossible.
In London, British Defence Secretary Liam Fox said some elements of the Gaddafi''s regime were in Sirte "where they are still continuing to wage war on the people of Libya." He said NATO would continue to strike at the Gaddafi forces'' military capability.
"The regime needs to recognise that the game is up," Fox said.