Libyan leader Muammar Gaddafi's forces have reportedly launched a fresh air assault against rebels who control the country's key eastern oil town of Brega.
Air force warplanes bombed the town's airport, as the area was targeted for a second day, according to rebel Captain Bashir Abdul Gadr.
There were also air strikes on a rebel position in the nearby town of Ajdabiyah, it was claimed.
No-one was thought to have been hurt in the Brega attack.
But a few rebel fighters were taken to hospital after a mortar they were handling exploded.
The latest assaults come after opposition groups repelled a ground and air attack on the town by troops loyal to Colonel Gaddafi on Wednesday.
Opposition soldiers also said pro-regime forces had been pushed back to Ras Lanuf, home to another major oil terminal and 375 miles east of capital Tripoli.
Brega is the site of Libya's second-largest petroleum facility and has been held by the opposition since last week.
The rebels, armed with rocket launchers, anti-aircraft guns and tanks, control the east of the country.
They have called for UN-backed air strikes against foreign mercenaries allegedly fighting for the Libyan leader.
But Western officials expressed caution about any sort of military involvement, including imposing a no-fly zone.
The Arab League said it was against direct outside military intervention, but could enforce a no-fly zone in co-operation with the African Union.
But, realistically, only the United States could carry out such an operation.
The rebels, armed with rocket launchers, anti-aircraft guns and tanks, control the east of the country.
They have called for UN-backed air strikes against foreign mercenaries allegedly fighting for the Libyan leader.
But Western officials expressed caution about any sort of military involvement, including imposing a no-fly zone.
The Arab League said it was against direct outside military intervention, but could enforce a no-fly zone in co-operation with the African Union.
But, realistically, only the United States could carry out such an operation.
For the past week, pro-Gaddafi forces have been focusing on Libya's west, securing capital Tripoli and trying to take back nearby rebel-held cities.
But its forces have seemed to have struggled in cities largely defended by local residents using weapons looted from storehouses and backed by allied army units.
Meanwhile, Arab League Secretary-General Amr Moussa said a peace plan for Libya from Venezuela's President Hugo Chavez was under consideration.
But Mr Moussa denied he and Col Gaddafi had already agreed to Mr Chavez's plan to send representatives from several countries to Libya.
The chairman of the rebel National Libyan Council, Mustafa Abdel Jalil, has reportedly said he rejected the concept of talks with the Libyan dictator entirely.