The win by the opposition comes as officials in Tripoli decided to retreat forces loyal to Moammar Gadhafi following nearly two months of laying siege to the western city.
Meanwhile, the Pentagon said the U.S. Air Force carried out its first Predator missile strike in Libya on Saturday. No details were given about the strike.
Libyan government officials showed evidence of an airstrike near Gadhafi's compound in Tripoli that it said caused no injuries, but it was not clear if that site was the Predator's target.
Opposition forces in Libya's third-largest city had held firm after being pounded by the government's heavy weapons for weeks. Friday, a top Libyan official said troops would be withdrawn and local tribes would take up the fight.
The only fighting Saturday was on the eastern outskirts of the city, where about 150 pro-Gadhafi soldiers trying to withdraw were fighting rebels.
On Thursday, Defense Secretary Robert Gates said President Barack Obama had approved the use of armed Predator drones to improve the precision of strikes on Libyan government forces.
Predators had previously been used in Libya only for surveillance. The low flying Predators have been used in Afghanistan to kill militants and are suited for urban combat.
NATO stepped into the Libyan fighting in mid-March, unleashing airstrikes against Libyan military targets as part of a U.N. mandate to protect civilians.
Meantime, rebel forces got a show of support from Sen. John McCain. The senator spent Friday in the rebel's stronghold of Benghazi.
McCain called for increased military support for the rebels including weapons, training and stepped-up airstrikes.
The Associated Press contributed to this report.