Libya: Fierce fighting south-west of Tripoli
Rebel forces in Libya have clashed with troops loyal to Col Muammar Gaddafi about 80km (50 miles) south-west of the capital, Tripoli.
A rebel spokesman in the Nafusa mountains said there had been heavy fighting on the outskirts of the strategic town of Bir al-Ghanam.
The rebels told the BBC they were making a push for Tripoli.
Meanwhile the International Criminal Court is to decide whether to issue an arrest warrant for Col Gaddafi.
A decision by a three-judge panel is expected at 1100 GMT. The ICC's chief prosecutor has also requested arrest warrants for Col Gaddafi's son, Saif al-Islam, and the head of Libyan intelligence, Abdullah Senussi.
The warrants are for alleged crimes against humanity committed against opponents of the regime.
The international military operation in Libya entered its 100th day on Monday, with the rebels still struggling to take advantage of coalition air strikes on Col Gaddafi's infrastructure.
The Libyan news agency reported fresh strikes on Tripoli overnight.
The rebels control the east of the country as well as pockets of western Libya, including the Nafusa mountains.
Guma el-Gamaty, a spokesman for the rebels' National Transitional Council (NTC), told AP news agency that Bir al-Ghanam - the focus of the latest fighting - was important as it was barely 30km (18 miles) south of Zawiya, a western gateway to Tripoli.
Opposition fighters seized Zawiya in March before government troops drove the rebels out of the oil-refinery city. Fighting again broke out there this month.
The BBC's Mark Doyle, who is in the village of Bir Ayad near Bir al-Ghanam, says Sunday's fighting began when government forces tried to cut off the rebels by attacking from behind.
Clashes continued in the distance, where the boom of artillery, the rattle of automatic gunfire and the occasional rumble of Nato jets could be heard, he says.
A medic said two rebels had died in the battle. The rebels said government forces suffered far greater casualties, although that cannot be confirmed.
The rebels came down into the plains from the Nafusa mountains in early June, adds our correspondent. But they have met strong resistance from Col Gaddafi's forces.
He says that although it is a shifting front line, the rebels appear to be gradually consolidating their position in the mountains.
"We are on the southern and western outskirts of Bir al-Ghanam. There were battles there most of yesterday," a rebel spokesman in nearby Zintan, Juma Ibrahim, told Reuters, adding that they had captured some government equipment and vehicles.
He said it was quieter now but that the rebels were "still in their positions".
The minister of defence for Libya's rebels, Jalal al-Dgheli, told the BBC that because their weapons were so limited, most of them were focused on the push from the western mountains towards Tripoli.
But in the near future there could be an advance from the east near Brega towards Tripoli, he told the BBC's Bridget Kendall in the rebel stronghold of Benghazi.
"What we're learning from defectors is that Gaddafi's supporters are getting fewer, people who are close to him are abandoning him, and his inner circle is getting smaller by the day."
He added that he hoped Col Gaddafi could be gone by the Muslim holy month of Ramadan, in August, but our correspondent said this could be wishful thinking.
The Libyan government on Sunday meanwhile reportedly renewed its offer for a vote on whether Col Gaddafi should stay in power.
Gaddafi spokesman Moussa Ibrahim was quoted as telling reporters in Tripoli that the government was proposing a period of national dialogue and an election overseen by the UN and African Union.
"If the Libyan people decide Gaddafi should leave he will leave," Mr Ibrahim was quoted by Reuters news agency as saying. "If the people decide he should stay he will stay."
But he said Col Gaddafi - who has run the oil-producing country since a military coup in 1969 - would not go into exile.
The idea of holding an election was first raised earlier this month by Saif al-Islam Gaddafi.
Since then Italy has called for a political settlement to the conflict, following a Nato strike in Tripoli on 19 June that killed several civilians.
Meanwhile, Tunisia's Tap state news agency reported that three Libyan government ministers, including the Foreign Minister Abdelati Obeidi, were in Tunisia for talks with "several foreign parties".
The agency gave no further details about what the negotiations involved.
In a separate development, African leaders meeting in Pretoria said Col Gaddafi has agreed to stay out of talks aimed at ending the conflict.
In a communique after talks on Sunday, the African Union panel on Libya said it welcomed "Col Gaddafi's acceptance of not being part of the negotiations process".
The statement did not elaborate.