Reinforced with weapons from a French arms drop and backed by NATO-led air strikes aimed at destroying Gaddafi's frontline armour, they attacked regime forces in the plains southwest of the capital.
The area targeted by that offensive is seen as strategic as it also features the garrison city of Gharyan, a government stronghold in the Nafusa mountains.
In Washington, the US House of Representatives debating an annual Pentagon spending bill voted 225-201 today to forbid the Pentagon from providing military equipment, training, advice or support to the Libyan rebels.
An AFP correspondent embedded with the rebels reported intense exchanges of artillery, mortar and cannon fire around Gualish on Wednesday.
NATO listed seven targets where Gaddafi's military equipment had been attacked, including eight armoured vehicles and military refuelling equipment near the eastern oil town of Brega.
An anti-aircraft gun was also destroyed near Gharyan. Eight armed vehicles were also hit in the Zlitan area.