BRUSSELS -- NATO says time is running out for Muammar al-Qaddafi as opposition forces advance, air strikes continue to inflict losses and regime officials flee.

Secretary-General Anders Fogh Rasmussen said Wednesday the alliance had destroyed 2,700 "legitimate military targets" since the campaign began in March. This includes 600 tanks and artillery pieces and 800 ammunition stores.

Still, Fogh Rasmussen warns that Qaddafi's forces remain a threat, saying that "without NATO there would be a massacre."

NATO's campaign was intended to deliver a sharp, devastating military blow that would allow the opposition to quickly oust his regime. But with the campaign dragging on inconclusively, there have been increasing international calls for a negotiated end to the war.