NATO says its missiles have hit a site in Libya used by leader Muammar Gaddafi's forces to stockpile military supplies and vehicles.
Libyan state media said 15 civilians had been killed in the attack late on Friday in the coastal city of Brega, about 200 kilometres west of the rebel stronghold of Benghazi.
The attack was the second within hours on what NATO said were clearly identified military targets.
A NATO official said the buildings hit were occupied and used by pro-Gaddafi forces to direct attacks against civilians around Ajdabiya, which is held by rebels.
Libyan state television said a local bakery and a restaurant had been hit, wounding 20 people in addition to the 15 dead. NATO said it had no indications of civilian casualties.
Colonel Gaddafi's government says more than 700 civilians have been killed in three months of Western air strikes.
The alliance acknowledged accidentally killing civilians in a strike on Tripoli a week ago, but has otherwise said it hit only military targets.
Meanwhile, a top rebel official said rebels would be ready to discuss any political settlement that did not involve Gaddafi remaining in power, although no proposals had emerged yet at talks with Gaddafi allies that were taking place through intermediaries.
An international coalition began carrying out strikes on forces loyal to Colonel Gaddafi in March, under a UN mandate to protect Libyan civilians.