A spokesman for the Libyan National Transitional Council said this morning that there was no confirmation yet that Mutassim Gaddafi, one of the former leader's sons, had been captured at Sirte.

Jalal el-Gallal, a spokesman for the Council in the eastern city of Benghazi, said his office had called commanders in the besieged city of Sirte and "so far as we are concerned there is no confirmation that Mutassim Gaddafi has been captured".

He was commenting following reports that the son had been seized, which prompted heavy celebratory gunfire in Tripoli and the eastern city of Benghazi.

Anti-Gaddafi fighters have been closing in on armed supporters of the fugitive leader in Sirte, the most important of two major cities yet to be cleared of loyalists more than two months after the fall of Tripoli.

Libyan officials have said they believe Mutassim Gaddafi and other high-level former regime figures are hiding in Sirte and that is the reason for the fierce resistance.

Mutassim was Libya's national security adviser and had a strong role in the military and security forces under his father's regime.

Libya's de facto leader, Mustafa Abdul-Jalil, said yesterday he expected to declare total victory in less than a week, as the International Committee of the Red Cross warned thousands of civilians were still trapped inside Sirte.

Muammar Gaddafi is still on the run and his supporters also hold the desert enclave of Bani Walid. But the transitional leadership says Sirte's capture will give them full control of the country's ports and harbours, allowing them to move forward with efforts to restore normality and establish a democracy.

Humanitarian workers are struggling to help civilians who lack food, clean water and other basic necessities. Red Cross staff evacuated 25 war-wounded and other patients, including a newborn baby in its incubator, from the main Ibn Sina hospital in the coastal city on Monday and Tuesday. Few doctors or nurses remained, the Red Cross said.

"The situation inside the hospital is very chaotic and distressing," the ICRC's Patrick Schwaerzler said. "When we arrived there we found patients with severe burns and shrapnel wounds. Some had sustained recent amputations. A few were half-conscious. They were lying among crowds of other people who were also asking us for help."

The hospital has been partly destroyed and is no longer functional, he added.

Most families have fled the fighting, but a few remain, either because they are fighting revolutionary forces or had no choice.

"My father is old and disabled and I couldn't leave him. He's 90 years old and lives with me, so we stayed. Whatever happens, we can do nothing about it," 42-year-old Ali Aggi said as revolutionary officials visited his home while his three sons looked on. His father, also named Ali, lay in bed, too old and feeble to talk.

NTC officials promised to arrange to have his father evacuated, giving Ali a chance to leave with the rest of his family. He said he would make a decision in coming days.

"We saw hundreds of civilians fleeing Sirte yesterday and today, but thousands are still caught inside the city," Mr Schwaerzler said, adding there was no electricity and civilians had received no food for weeks.

He called on all parties to take all possible precautions to spare civilians.

More than 20,000 people, among them many women, children and elderly people, have so far left their homes in Sirte. In addition, dozens of people have been arrested in recent days.

Libya's new rulers have promised to declare victory after Sirte is captured and to name a new government that will guide the oil-rich North African nation to elections within eight months.

"I hope that liberation will be declared in less than a week, after we free Sirte, and within less than a month we will form a transitional government and the youth and women will have a role in that," Mr Abdul-Jalil said.

He spoke at a joint news conference with Tunisian prime minister Caid Essebsi, who was visiting Benghazi to restore the two countries' once-lucrative trade ties.

Mr Essebsi met Mr Abdul-Jalil and other Libyan officials during his one-day visit, his first trip since Gaddafi was forced into hiding as Tripoli fell to revolutionary forces in late August.

Several world leaders and dignitaries have travelled to the oil-rich North African nation as the international community rallies around the new rulers. Nato also has promised to continue its mission until Gaddafi forces no longer pose a threat to civilians.