At least 11 people were killed and dozens more wounded on Tuesday in an artillery barrage launched by forces loyal to Libyan leader Muammar Gaddafi on the besieged city of Misurata, according to rebel sources.
"Eleven people were killed and 57 wounded, almost all of them civilians," a rebel told the AFP news agency from Misurata after the attack.
The shelling marked another bloody day for a city that has been bombarded almost continuously since March.
Sources said five rebels were killed in fighting at the western entrance to the city earlier in the day.
On the same day, France's defence minister, Gerard Longuet, had questioned the rebels' chances of defeating Gaddafi's troops and eventually pushing towards the capital, Tripoli, some 200km to the east.
The concern came amid rebels' claims that they had begun a ground offensive against a key gateway to Tripoli. There was no independent verification of the rebels' new campaign.
The rebels have a "growing capacity to organise politically and militarily" but are "currently not in a stabilised, centralised system", Longuet said.
He added, however, that the rebels were no longer in need of controversial French weapons drops.
"There is emerging a political order distinct from that of Tripoli. The [rebel] territories are organising their autonomy... That is why the parachute drops are no longer necessary," he said.
Across the Gulf of Sirte, on the conflict's eastern front line, a rebel representative said nine Gaddafi soldiers were captured between Ajdabiya and Brega.
Despite the ongoing violence, diplomatic negotiations continued this week over a possible solution to the conflict, although no proposal appears to have gained much traction.
An unnamed senior Russian official was quoted on Tuesday as saying Gaddafi would consider stepping down under certain circumstances. His departure, if realised, would meet the rebels' central demand.
"The colonel is sending signals that he is ready to cede power in exchange for security guarantees," the daily Kommersant newspaper quoted the official as saying.
The Russian source added that France appeared to be the country most willing to play a part in Gaddafi's potential transfer of power. He said Paris could choose to unfreeze some of the Gaddafi family's accounts and promising to help him avoid trial at the International Criminal Court in The Hague.
The rebels have rejected any proposed deal that would leave Gaddafi in power.
"There is no escape clause for Gaddafi - he must be removed from power and face justice," Mustafa Mohammed Abdel Jalil, head of the rebels' Transitional National Council, said earlier this week.
Peparations were underway for an international meeting on Libya in Istanbul on July 15-16. Mahmud Jibril, the foreign affairs point man for the rebels, held talks with his Turkish and UAE counterparts on Tuesday.
Recep Tayyip Erdogan, the prime minister of Turkey, whose country is NATO's sole Muslim-majority member and an influential regional player, has called on Gaddafi to cede power and leave Libya.
This month's meeting comes as diplomats debate what post-Gaddafi Libya might look like, with many hoping to avoid the chaos left in post-conflict Iraq or Afghanistan.
Anders Fogh Rasmussen, the NATO chief, said on Tuesday that the alliance would like to see the United Nations assume the leading role in Libya's transition to democracy in the event Gaddafi leaves power.
"To accommodate the legitimate aspirations of the Libyan people, it is necessary that Gaddafi leaves power," said Rasmussen.
"After that, it is necessary to ensure a transition to democracy... We want the United Nations to take the lead in this effort," he added.
One of the new elements in a plan agreed on by the African Union on Friday includes provisions for a multinational peacekeeping force organised by the United Nations.
Rasmussen is to meet Libyan opposition members in Brussels next week the rebels' first invitation to NATO headquarters, an alliance diplomat said on Tuesday.