In a barely audible telephone call to state television overnight, a defiant and apparently isolated Gaddafi called on his followers to fight rebels he referred to as “rats.”

Gaddafi’s forces fired mortars and rockets at the coastal town of Zawiyah a day after rebels captured its center in a thrust that severed the vital coastal highway from Tripoli to the Tunisian border, a potential turning point in the war…

Rebels may still lack the manpower for an all-out assault on Tripoli, but are hoping their encirclement of the capital will bring down Gaddafi’s government or inspire an uprising. In the past, however, they have frequently failed to hold gains, and a fightback by Gaddafi troops could yet break the siege.