The fresh attack into the Mediterranean coastal city of Sirte contrasted with a stalemate in the mountain enclave of Bani Walid where demoralised anti-Gaddafi forces tried to regroup after being beaten back by loyalist snipers and gunners holding strategic high ground.
Intense resistance has stalled forces of Libya's new leadership trying to crush the dug-in fighters loyal to Gaddafi, weeks after the former rebels swept into Tripoli on Aug 21 and pushed the country's leader out of power and into hiding.
Sirte and Bani Walid are the main bastions of backers of the old regime in Libya's coastal plain, but smaller holdouts remain in the deserts of the center of the country, and another major stronghold, Sabha, lies in the deep south.
The resistance has raised fears of a protracted insurgency of the sort that has played out in Iraq and Afghanistan, even as the transitional government tries to establish its authority and move toward eventual elections.
A military spokesman for the transitional government said revolutionaries do not know Gaddafi's location.
Col Ahmed Omar Bani pointed to the still uncollected bounty of nearly USD 2 million that the new leadership has put on the fugitive leader's head, saying, "Up to now we don''t have any certain information or intelligence about his whereabouts."