The attack late on Friday was the second within hours on what NATO said were clearly identified military targets in the coastal city of Brega, around 200 km west of the rebel stronghold of Benghazi.
Libyan state television said a local bakery and a restaurant had been hit, wounding 20 people in addition to the 15 dead. State news agency Jana said a strike in the same area earlier on Friday had killed five civilians.
"We have no indications of any civilian casualties in connection to these strikes," a NATO official said. "What we know is that the buildings we hit were occupied and used by pro-Qaddafi forces to direct attacks against civilians around Ajdabiyah," the official said of a nearby opposition-held town.
"Unlike the pro-Qaddafi forces, we go to great lengths to reduce the possibility of any civilian casualties."
Separately, a Reuters correspondent in the capital Tripoli heard a total of four loud explosions as jets flew overhead on two occasions on Saturday. The blasts appeared to come from the eastern suburb of Tajura. Several other explosions shook the city late Friday.
NATO acknowledged for the first time last week that one of its raids in a three-month campaign could have caused civilian casualties, prompting concerns within the alliance.
Italian Foreign Minister Franco Frattini said NATO's credibility was at stake and called for a suspension in the campaign — an appeal that was swiftly knocked down at NATO headquarters and by allies, including France and Britain.
In a televised address this week, Qaddafi branded NATO "murderers" and vowed to fight to the death to stay in power.
The bombing campaign of the NATO-led coalition is into its fourth month in support of Libyan opposition seeking to end Qaddafi's 41-year-old rule. Recent progress has been slow and anti-government fighters have taken many casualties, but there are signs Qaddafi's forces are also being stretched and the local economy hit by international sanctions.
In a morale-booster for the opposition, at least four members of Libya's national football team and 13 other football figures defected. They included national goalkeeper Juma Gtat and Adel bin Issa, the coach of Tripoli's top club Al-Ahly. The defections were announced in the opposition-held Nafusa Mountains in western Libya.
The announcement was made in a video posted Saturday on a Facebook page under the title "the national team announces its defection." In it, several of the men said they were visiting the Nafusa mountains to show support. The speakers did not identify themselves by name.
One of them said they were "announcing — not from now but from the beginning of the revolution — that we are joining it." Another said, "God willing, Tripoli will be liberated by this mountain. This is a message to the agents to abandon their weapons because Libya will be free, sooner or later."
Meanwhile, opposition representatives said their fighters were coordinating around the country for the "zero hour" when their forces would reach the capital, Tripoli.
They said they have been working to cut fuel supplies from Tunisian borders in an attempt to paralyze Qaddafi's forces. The fighters also are making homemade bombs and trying to ferry other weapons to their comrades in Tripoli, a spokesman for an underground guerrilla group there said.
Anti-government forces have taken over much of the eastern half of Libya. They also control pockets in the west, including the vital port city of Misrata, about 200 km from the capital.
