Libyan rebels beat a fresh retreat from Brega on Sunday after a new bout of fierce fighting over the key oil town, an AFP correspondent reported.
Rebel fighters, who had entered the frontline town just hours earlier, said they were staging a tactical withdrawal after being ambushed by loyalists of veteran strongman Muammar Gaddafi.
The AFP correspondent saw some 300 to 400 fighters regrouping on the road back into rebel-held territory some 10 kilometres (six miles) to the east.
Loud explosions rocked the desert landscape as the retreating forces came under artillery fire.
The rebel fighters riposted with rockets, shouting "Allahu Akhbar (God is Greatest)" after each salvo.
Aircraft from the NATO-led coalition enforcing a no-fly zone were heard overhead.
Earlier on Sunday, the rebels had pushed forward to seize the vast university campus on the outskirts of Brega, an AFP correspondent witnessed before the retreat.
The town has been the scene of intense exchanges for several days with both sides advancing only to pull back under fire.
On Saturday, the rebels had claimed to have recaptured Brega, 800 kilometres (500 miles) east of the capital Tripoli, but pro-Gaddafi snipers were said to be still active and others were apparently holed up in the university.