Rebels in the western Libyan town of Zliten were said to be low on ammunition and on the defensive on Sunday, as the regime said its forces had retaken the strategic southwest town of Bir Ghanam.
Abdul Wahab Melitan, a rebel spokesman in the port city of Misrata near Zliten, said forces loyal to strongman Moamer Kadhafi had launched an assault on rebel positions in Zliten's Souk Telat area, killing three and wounding 15.
"The rebels lack ammunition to advance and we do not want to risk losing any ground," Melitan said.
Meanwhile, a rebel source at Al-Qusbat, around 90 kilometres (55 miles) east of the capital Tripoli, said that town was living through its fourth day under siege.
A group of rebels on Thursday overran Kadhafi forces based in one of the town's schools, but since then the rebels have been battling to hold on to their gains.
Raed Hussein, an envoy from Al-Qusbat's military council, said he expected more Kadhafi troops to be sent from nearby Al-Khums to bolster the siege.
In Tripoli, Prime Minister Baghdadi Mahmudi told reporters that government troops had recaptured the strategic town of Bir Ghanam, southwest of the capital, from insurgents.
"Life is back to normal in Bir Ghanam, and today it is under the full control of the regime," Mahmudi said.
Rebels from the Berber-dominated Nafusa mountain range south of Tripoli claimed the capture of Bir Ghanam just 80 kilometres from the capital on Saturday, as they pushed further east.
An AFP correspondent on the scene said rebels began a two-pronged assault from Bir Ayad earlier that day, and by late afternoon, rebel commanders said Bir Ghanam had been seized.
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The rebels have been using the Nafusa as a springboard to advance on Tripoli but have encountered strong resistance from fighters loyal to Kadhafi.
Mahmudi also condemned the intensification of NATO raids on Tripoli and other cities, claiming that the alliance no longer "differentiates between civilian and military sites."
NATO said its warplanes attacked 45 targets across Libya on Saturday, including an ammunition storage facility and a multiple rocket launcher system in the Bir Ghanam area.
Mahmudi criticised the National Transitional Council (NTC), the rebels' de facto government, and the security situation in the rebel-controlled east, especially after last month's assassination of General Abdel Fatah Yunis, a long-time Kadhafi ally before he defected.
The premier claimed that the "decision-making and the real forces in the field are in the hands of Islamist extremist groups."
Since the beginning of the revolt, the Kadhafi regime has portrayed the five-month-old uprising as an Al-Qaeda plot.
Mahmudi also claimed that most NTC members had left the country, saying: "I defy the NTC to meet even once during Ramadan," the Muslim month of fasting.
On Saturday, hundreds of rebel fighters also forked off towards the sea, advancing within 20 kilometres of Surman on the coast road west of Tripoli before meeting any resistance, an AFP correspondent said.
Their path northward was veiled in black smoke and strewn with burned-out Libyan army vehicles, some with the bodies of soldiers inside, he said.
But forces loyal to the veteran Libyan strongman fought back, laying down fire in a bid to halt the rebels' advance.
Many of the rebels were from the "Tripoli Battalion," a group of volunteers from the capital and other coastal towns eager to "liberate" their homes in the five-month-old revolt.
The battalion is said to have received military training in the Nafusa mountains.