The National Transitional Council (NTC), Libya's new rulers, suffered setbacks on the political front when last-minute haggling over portfolios forced an indefinite delay in announcing a cabinet line-up.
Mussa Ibrahim, defeated leader Muamer Gaddafi's spokesman, boasted in a phone call to Syria-based Arrai television channel that loyalist troops have won several battles in the past few days against NTC fighters.
The commander of the NTC's Al-Qabra brigade, Walid al-Feturi, said Sunday they were clearing the roads in Sirte for fleeing civilians before launching a new assault on the Mediterranean city, which has a population of about 130,000.
"The first problem is that there are children and civilians inside and we don't want to use Grad rockets or heavy artillery," Feturi told AFP on the edge of Sirte.
"But on the other side they are shooting at us with heavy machine guns and artillery," he said. "We are trying to get out family and children step by step."
Frontline fighters in Sirte are convinced that Mutassim Gaddafi, a career soldier and former national security advisor to his father, is hiding in the southern outskirts of the one-time strongman's hometown.
The whereabouts of the toppled Gaddafi and his children have been the subject of countless rumours since he fled Tripoli as rebel forces advanced.
Radio chatter intercepted by former rebels showed a lieutenant by the code name of Abu Bakr issuing orders to Gaddafi loyalists to shoot heavy artillery despite counter-appeals to protect civilian life, an AFP journalist said.
"Shoot, shoot," crackled the radio. "We don't need them. You have experience in Chad. Just shoot."
NTC fighters said that the same pro-Gaddafi commander promised to come to Mutassim's rescue saying: "Master, master... we will protect you as ordered by your father." That report could not be verified by Misrata's military council.
The new regime's forces were also approaching Sirte from the west, and on Sunday overran the town of Harawa, 60 kilometres away (38 miles), an AFP correspondent said. The town was captured after hours of fierce fighting that pitted Gaddafi diehards against NTC fighters armed with anti-aircraft guns, rocket-propelled grenades, Katyushas and backed by tanks.
Mustafa bin Dardaf, one of the commanders of the Zintan Brigade leading the western advance, said that late on Sunday NTC forces had also entered the town of Sultana 38 kilometres west of Sirte, and would push forward on Monday.
Gaddafi loyalists were meanwhile also putting up stiff resistance in Bani Walid, southeast of Tripoli, an AFP correspondent said.
On Sunday, the NTC's forces were beaten back after pushing into the town. Correspondents heard loud explosions and intermittent gunfire from inside the town, and rockets exploded near NTC positions on the outskirts.
Gaddafi spokesman Ibrahim, without disclosing his whereabouts nor that of his boss, said loyalist troops had been victorious in the latest fighting. "We have won several battles against the NATO collaborators and managed to push them out of Bani Walid and Sirte," he said. "In spite of deadly NATO strikes our forces resist and our fighters pursue their fight because we are involved in a battle for dignity and against the forces of evil."
Ibrahim said he was confident that the capital Tripoli would be "reconquered." "We will be back in all towns and cities that have been occupied by the NATO mercenaries. We promise you that we will bury the colonialist project targeting the Arab people."
The birth of a new government in Libya, which had been scheduled for Sunday, has been postponed due to squabbling over portfolios. "The announcement of a new transitional government has been postponed indefinitely in order to finalise consultations," NTC number two Mahmud Jibril told reporters in the eastern city of Benghazi.
But in an apparent effort to put on a brave face, Jibril said much has been achieved to deal out several portfolios, adding that he expected consultations on the rest to be "over quickly." "But I believe that an essential part of these consultations was completed today."
The administration will also look into getting women and young people to play a major role in a new government as deputy ministers and directors general of ministries, he added.
Jibril, a former Gaddafi regime official, has stood accused by some colleagues of failing to consult enough with long-standing grass roots opposition groups such as the Muslim Brotherhood.