Italy's call for a ceasefire exposes the strain on the NATO alliance. Nearly 14 weeks of bombing have so far failed to overthrow Gaddafi. NATO is facing mounting pressure over the cost of the conflict and rising civilian casualties. Rasmussen said the allies are committed to making the necessary efforts to sustain the operation.

US, British and French leaders have said they will keep up the pressure until Gaddafi steps down. But rebels opposing him have been unable to break through his defenses and advance on the capital Tripoli.