NATO says it has sunk eight Libyan warships and intercepted a fuel tanker it believed was to deliver fuel to government forces.
Air strikes have been carried out on Tripoli, Al Khums and Sirte.
The alliance says its strikes on command-and-control centres have limited Colonel Muammar Gaddafi's ability to control his forces, as well as relieving sieges of rebel areas.
NATO is operating under a UN mandate to protect civilians.
Secretary General Anders Fogh Rasmussen said earlier on Thursday that Colonel Gaddafi's forces were becoming more isolated every day.
