Heavy fighting has been continuing in Libya between government and rebel forces, who are still battling for the oil town of Brega.
At one point, both sides simultaneously claimed control of the town.
A UN envoy is in the country, asking for an end to the violent response to opposition protests and immediate humanitarian access.
In the west, government forces have moved into the rebel-held town of Zuwara and are shelling Misrata city.
But the focus has also moved east to Ajdabiya, the last town before the rebel base in Benghazi.
It seems rebel fighters have been hiding inside the oil installation in Brega in the daytime, in the belief that the government does not want to shell the facility, says the BBC's Jon Leyne in Benghazi.
Opposition sources are also saying there are divisions within the government ranks, with some troops apparently reluctant to fire on civilians, our correspondent adds.
US meets opposition leader
UN envoy Abdul Ilah Khatib has met Libyan Foreign Minister Moussa Kusa in the capital, Tripoli.
In the meeting, Mr Khatib, a former Jordanian foreign minister, reiterated demands for an end to the violence and requested access for humanitarian groups, a UN spokesman said.
Foreign ministers of the G8 industrialised nations are discussing the crisis in Paris - but the BBC correspondent there says it is already clear that there are divisions over whether any intervention would be effective.
France is pushing for a no-fly zone that would ground Libyan aircraft to protect people from assault by forces loyal to Libyan leader Col Muammar Gaddafi.
But the US, Russia and other EU countries had reacted cautiously to the no-fly zone proposal ahead of the Paris meeting.
US Secretary of State Hillary of Clinton - who is attending the Paris meeting - has met a leader of the new opposition in Libya, Mahmoud Jibril, for 45 minutes at a Paris hotel and discussed ways the US could assist beyond humanitarian aid.
