Nato resumed its airstrikes on the Libyan capital of on Tuesday night, blasting at least two targets just before midnight, after military leaders voiced concerns about sustaining the operations if the alliance mission drags on.
The targets of the late night airstrikes were not immediately clear, and there was no word about casualties.
East of the capital, alliance aircraft have begun dropping leaflets warning government troops to abandon their posts outside Zlitan, which lies just west of the rebel-held port city of Misrata.
Rebel forces have been advancing along the Mediterranean coast toward Zlitan, but say they have been instructed by Nato to withdraw ahead of expected bombing runs to old front lines in Dafniya.
The leaflets intended for forces loyal to Muammar Gaddafi carry the Nato symbol and a picture of an Apache attack helicopter and burning tanks on one side.
Green Arabic writing warns: "There's no place to hide. It's not too late to stop fighting. If you continue to threaten civilians, you will face destruction."
The message on the reverse urges soldiers to "stop and stay away from fighting now".
If the rebels take Zlitan, they would be within 85 miles of the eastern outskirts of Tripoli.
A rebel official said opposition leaders in Zlitan have been meeting with their counterparts in Misrata, but he acknowledged they face challenges in advancing on the city.
"We need the people of Zlitan to push more courageously forward. They are dependent on our movements, but the problem is only a third of that city is with the rebels," said Ibrahim Beatelmal, a rebel military spokesman in Misrata.