NATO voiced concern on Saturday about reports of civilian deaths in a coalition air strike near Brega as rebels claimed victory in the battle for the key Libyan oil town.
A rebel spokesman in the town of Misrata, 214 kilometres (132 miles) east of Tripoli, also reported fierce fighting there on Saturday.
The chief rebel spokesman told reporters coalition warplanes had killed 13 people, four of them civilians, in an air raid some 15 kilometres east of Brega on Friday.
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"Thirteen dead, seven injured by friendly fire. It was a regrettable occurrence," Abdulhafiz Ghoga said, calling them "unintentional deaths."
"The leadership is working on preventing a re-occurrence," he added.
Earlier, a civilian rebel official said the dead civilians were an ambulance driver and three medical students from Libya's second city of Benghazi, the rebel stronghold in the east.
They had been part of a rebel convoy of five or six vehicles, said Issa Khamis, liaison officer for the rebels' transitional government in the town of Ajdabiya, east of Brega.
A spokeswoman for NATO, which leads the international coalition enforcing the no-fly zone over Libya and protecting civilians from attack, said the alliance was checking.
"We are looking into these reports," said Oana Lungescu. "We are always concerned by reports of civilian casualties. NATO's mission is to protect civilians and civilian areas from the threat of attack."
No formal investigation had been launched, she said.
Friday's air strike came as rebels shot tracer fire into the air to celebrate the entry of an advance column into Brega.
"It was a mistake" by the rebels, Khamis said. "The aircraft thought they were coming under attack and fired on the convoy."
Ghoga also said Brega had now fallen.
"Brega is fully under the control of the rebels," he told the news conference.
Earlier on Saturday, an AFP correspondent reported fighting was still going on both inside and outside Brega.
Rebels with only light arms were being told to stay back, and several said forces loyal to embattled Libyan leader Muammar Gaddafi were holed up in the university in Brega, 800 kilometres (500 miles) east of Tripoli.
Loyalist forces "are surrounded inside the university. The rebels have surrounded them and they can't get out," said fighter Abdel Khalak Ali, 20, who was ordered to pull back because he had only a Kalashnikov assault rifle.
A correspondent saw seven bodies of Gaddafi loyalists and at least 10 burnt-out pick-up trucks on the road between Ajdabiya and Brega, 80 kilometres to the west, bearing witness to the bitter fighting.
Jubilant rebels told how a strike by coalition aircraft took out at least two vehicles in a convoy of seven heavily armed pick-ups, and they finished off the rest with rocket-launchers in an ambush from a eucalyptus grove.
The vehicles of the pro-Gaddafi convoy and even the bodies were looted during the night and stripped of anything useful.
The rebels had already taken any serviceable guns and ammunition as they seek to counter the huge superiority in weaponry of Gaddafi's forces.
Brega has been the scene of intense exchanges over the past few days when pro-Gaddafi forces returned after being driven out by the insurgents.
But it has been unclear since Thursday who actually held the town.
In Misrata
In the rebel-held town of Misrata, a rebel spokesman reported both close-quarters clashes and tank and artillery fire.
He said Gaddafi's forces tried to enter Misrata from three fronts, but were pushed back. Two rebels were killed, he reported.
The spokesman said snipers fired at anyone on the street, and reported a civilian car driver shot dead. Rebel fighters killed seven snipers, he added.
"These are true crimes which must be stopped. Gaddafi troops are endangering civilian lives and using prohibited weapons," he charged.
Southwest of Tripoli, the town of Ketla was targeted by dozens of Grad rockets by Gaddafi loyalists on Friday and Saturday, killing more than 30 people, residents reported.
French warplanes in action over Misrata on Friday launched an air strike on a tank, the military said in Paris.
Coalition forces also strafed loyalist positions in the Al-Khums and Al-Rojban regions east and southwest of Tripoli late on Friday, Libyan state television reported.
In Benghazi, Transitional National Council leader Mustafa Abdul Jalil said on Friday the opposition was ready for a truce, provided regime forces end their assaults on rebel-held cities.
Government spokesman Mussa Ibrahim dismissed the offer outright.
"The rebels never offered peace. They don't offer peace, they are making impossible demands," he told reporters, calling the truce proposal a "trick."
"We will not leave our cities. We are the government, not them," he said, adding however that the government was always ready to negotiate and wanted peace.
A rebel spokesman, Mustafa Gheriani, said Tripoli's rejection of the offer showed Gaddafi "wants no peace -- he wants to inflict as much damage on the Libyan people as possible before leaving power."
Gheriani admitted the rebels were a poor match for Gaddafi's better-trained, better-armed forces, but he said they would still prevail.
"We are outgunned, but we are the people," he said.
Three Swedish JAS Gripen fighter jets were heading for Sardinia en route to taking part in NATO operations in Libya, a military spokesman said on Saturday, adding that another five Gripens and a C-130 Hercules were to leave on Sunday.
A petition demanding the release of a young Libyan women who stormed into a Tripoli hotel full of journalists and accused government soldiers of rape was on the way to reaching its target of half a million signatures on Saturday.
Iman al-Obeidi achieved worldwide celebrity after footage of her bursting into the Rixos hotel last Saturday and throwing open her coat to reveal scars and bruises was posted on the Internet.
"Words cannot express the courage Iman showed in speaking out -- and we can only imagine the terror she must be facing right now in the hands of Gaddafi's infamous thugs," said Avaaz.org, organiser of the online campaign.
