Coalition forces have kept up pressure on Muammar Gaddafi with a relentless barrage of air strikes, as US officials said the veteran Libyan leader was arming volunteers to stave off the onslaught.
Explosions rocked an eastern suburb of Tripoli early on Saturday, and a witness said a military radar site was in flames on the eighth day of coalition air strikes.
Coalition warplanes pounded Gaddafi's forces in the strategic eastern town of Ajdabiya, boosting the efforts of rebels who have come under sustained assault from pro-regime forces.
Plumes of smoke filled the sky as the pace of the air strikes escalated, forcing terrified residents to flee the coastal city, 160 kilometres south of the rebel stronghold of Benghazi.
"We entered the town," Colonel Mohammed Ehsayer, who defected from the army to join the rebellion against Gaddafi, said at a rebel outpost a few kilometres east of the city.
"Soon the eastern and western gates (entry roads) will fall," he said referring to positions still in the hands of loyalist forces, with the uprising now in its fifth week.
Witnesses east of the city said the rebels were launching offensives in a bid to regain control of Ajdabiya, bolstered by the UN-mandated air strikes launched on Saturday by US, Britain, and France in a bid to protect civilians.
Gaddafi forces also pounded the rebel-held city of Misrata, 214 kilometres east of Tripoli, with artillery late on Friday, killing a mother and her four children, a witness said.
"The artillery shelling has been going on since Thursday night," said the witness contacted by telephone.
"They are firing on everything that moves."
"There is no water, no electricity and supplies are running short," in Misrata, Libya's third city, he said, adding residents were cowering indoors.
US warships and submarines had fired 16 new Tomahawk cruise missiles at Libyan targets in the 24 hours to 0500 GMT (1600 AEDT) Friday, the Pentagon said, adding that coalition warplanes carried out 153 sorties over the same period.
The total number of Tomahawks launched at Libya rose to at least 170.
Libyan state television reported that coalition warplanes also carried out raids late on Friday on the coastal town of Zliten, 160 kilometres east of Tripoli.
US officials said the relentless pressure on Gaddafi and his allies was beginning to take its toll.
"We've received reports today that he has taken to arming what he calls volunteers to fight the opposition," said US Vice Admiral William Gortney.
Until now, the Libyan leader is believed to have relied on militias run by his sons as well as African mercenaries to fight poorly-armed but determined opposition forces.
Gaddafi "has virtually no air defence left to him and a diminishing ability to command and sustain his forces on the ground," Gortney said, following seven days of coalition air raids.
"His air force cannot fly, his warships are staying in port, his ammunitions stores are being destroyed, communications towers are being toppled, his command bunkers rendered useless," Gortney said.
Gaddafi also appeared to be showing signs of strain as his key allies put out feelers to mediators, possibly over an exit strategy.
"It's clear that the regime is reaching out to several possible mediators, interlocutors to try to get a message across," Gene Cretz, the US ambassador to Libya, told reporters.
"I'm not exactly sure what the message is, but it clearly indicates, I think, at least some kind of desperation, I think, at this point," Cretz said.
Cretz praised the Libyan opposition national council saying it was "off to a good start" after issuing a document supporting human rights and women's rights, and adding the United States was considering recognising the group.
US President Barack Obama who has come under pressure at home for the launching new military action abroad was to address the nation late on Monday on the conflict in Libya.
French President Nicolas Sarkozy meanwhile held out hopes of a diplomatic initiative to end the conflict.
"There will certainly be a Franco-British initiative to clearly show the solution is not only military but also political and diplomatic," Sarkozy said, referring to key talks on Libya to be held in London on Tuesday.
NATO has named three-star Canadian general, Lieutenant-General Charles Bouchard, to run NATO's Libya operations, enforcing the UN-mandated no-fly zone and arms embargo.
Bouchard will also take command of the entire military campaign if the 28-member alliance agrees to take up the reins fully from the US-led coalition.
British Foreign Secretary William Hague said he expected NATO to take full command of military operations in Libya "within a matter of days".
Meanwhile, Libyan health ministry official Khaled Omar told reporters that 114 people have been killed and 445 wounded in four days of coalition strikes, from Sunday to Wednesday.
Omar said 104 people were killed in Tripoli and its suburbs, while 10 were killed in Sirte, Gaddafi's hometown, some 600 kilometres south of the capital.
The Pentagon said 12 countries were now taking part in the coalition seeking to enforce the no-fly zone, including Qatar and the United Arab Emirates.
Qatar on Friday became the first Arab country to take part in the military campaign, its air force and the French military announced.
Two Mirage fighter planes from Qatar carried out an "air interdiction mission" alongside two French jets, the French military said on its website.
