'Get ready for the fight,' Gaddafi tells loyalists as rebels advance on key towns

Progress in Zawiyah and Gharyan comes amid news of talks with regime officials in Tunisia

As Muammar Gaddafi issued a desperate demand that his supporters take up arms for a final battle in Libya's civil war, the country's rebels claimed to have dealt his hopes of remaining in power a significant new blow with the reported seizure of the town of Gharyan from regime forces.

Fight for the west: click here to download graphic

Even as the rebels celebrated their apparent victory, the scale of the task that remains before them was underlined when witnesses in the vital coastal city of Zawiyah said the opposition had been forced to retreat from the town centre they had taken control of on Sunday. Rebel forces were running low on ammunition as the battle raged, the Associated Press reported, and forced to take cover as they waited for more supplies to arrive.

At a hospital in Zawiyah, medics said six rebels had died and 26 were wounded. They also told Reuters that firing by Gaddafi forces had killed three civilians. One man was shot in the head and a 15-year-old girl died of shrapnel wounds.

In a sign that shows Gaddafi might seek an escalation in the conflict, it was reported last night that his forces had fired a Scud missile at rebel territory on Sunday. According to a US defense official, the missile was aimed at Brega, but overshot the target by about 50 miles and landed in the desert.

If the reports of success in Gharyan are true, they would add to the sense that the rebels and their Nato allies have finally broken the longstanding deadlock in the conflict. The news came as diplomatic sources disclosed that fresh talks are taking place between rebel and regime officials in Tunisia.

The possibility that the negotiations may be of significance was bolstered by the news that the UN envoy appointed for the crisis, Abdul Ilah al-Khatib, had arrived at short notice to join the talks in a hotel at the resort island of Djerba.

Abdulrahman, a rebel spokesman, said of the seizure of Gharyan: "[The town] is fully in the hands of the revolutionaries ... Gaddafi has been isolated. He has been cut off from the outside world."

Col Gaddafi meanwhile issued a plea for loyalists to "liberate Libya inch by inch from the traitors and from Nato". It was the first such message since the latest rebel assault began, delivered by a poor quality telephone line without pictures to the state broadcaster.

"Get ready for the fight," he said. "The blood of martyrs is fuel for the battlefield." But the message could not quell rumours – unsubstantiated – that South African aircraft had arrived in Tripoli to spirit away Gaddafi and his retenue.

The putative progress in Gharyan was not the only sign that the tide could be turning against the dictator. In what appeared to be the highest profile defection since the departure of foreign minister Musa Kusa, interior minister Nassr al-Mabrouk Abdullah landed in Cairo in a private jet yesterday, with nine members of his family.

Mr al-Mabrouk, who was known to be close to the Gaddafi family, was travelling on a tourist visa and later claimed to be in Cairo on holiday. The Libyan ambassador in the Egyptian capital, Ali Maria, said he had no information about the apparent defection. The embassy said later: "We had no idea of his arrival, but he was in Tunisia on Sunday".

However, that Mr al-Mabrouk was present at the Tunisia talks also led to the theory that he was there to inform Egypt's military government about the state of negotiations, although that did not explain the presence of his family members.

The rebels' military advances of recent days could be of vital importance because they threaten to cut Tripoli off entirely from the outside world, and could fatally choke the Gaddafi regime's fuel supplies. The only oil refinery under the regime's control is outside Zawiyah.

At present Gaddafi loyalists retain control of the site, and the rebels will face a complex challenge if they are to take charge of it without doing harm to the supply. In Zawiyah, rebel fighter Khalid Al-Zawi told Reuters: "Gaddafi is crazy. He's capable of absolutely anything. That's one thing we have to keep in mind."

Gharyan straddles the road to the south that connects Tripoli with another Gaddafi stronghold, Sabha. The seizure of the two towns would enormously tighten the siege on the Gaddafi regime.

David Cameron, who has faced growing political pressure over the stalemate in Libya, welcomed the progress, underlining the role the international coalition had played.