Rebels, meanwhile, said they were under intense attack by Gaddafi’s forces in the city of Misrata near Tripoli and an AFP reporter saw them beaten back from a frail attempt to retake the eastern key town of Ajdabiya.
In Cairo, the Arab League on Monday reaffirmed its support for Operation Odyssey Dawn after the previous day saying the air strikes led by the United States, France and Britain went beyond the scope of a UN resolution to implement a no-fly zone.
The operation was launched on Saturday to enforce UN Security Council Resolution 1973 aimed at stopping Gaddafi’s forces harming civilians as they battle a month-long uprising.
And as divisions over the air strikes emerged in Nato, the United States said the ultimate goal of the operation is the departure of Gaddafi.
British Prime Minister David Cameron, however, said there was no legal authority for regime change in Libya. The British parliament meanwhile overwhelmingly supported the country's involvement in the military operation.
Politicians voted 557 to 13 in favour of the action as British Typhoon fighter jets took part in their first ever combat mission, assisting coalition forces in patrolling the no-fly zone.
Libyan state television said the capital Tripoli came under attack after dark. Loud explosions and anti-aircraft fire ripped across the night sky near Gaddafi’s residence at around 19:00 GMT, an AFP reporter said.
Similar explosions rocked the capital on Sunday night, with coalition officials on Monday saying an administrative building in Gaddafi’s fortified complex had been destroyed by a cruise missile.
Witnesses said a Libyan navy base some 10km east of the capital was also bombarded late on Monday.
A Libyan government spokesperson, Mussa Ibrahim, told a Tripoli news conference coalition warplanes on Monday targeted the southern town of Sebha, bastion of Gaddafi’s Guededfa tribe. He did not indicate if any damage or casualties had resulted.
Ibrahim also claimed that Misrata, Libya's third city 214km east of Tripoli, was "liberated three days ago" and that Gaddafi’s forces were hunting "terrorist elements".
But a rebel spokesperson reached by telephone in Misrata insisted the insurgents remained in control despite an onslaught by Gaddafi loyalists, who he said opened fire with tanks and set snipers on roofs to gun down people in the streets.
A medic in Misrata, speaking by telephone against a background of gunfire, confirmed a death toll of 40 and said at least 300 people had been wounded.
"Casualties fell in their dozens," after snipers and a tank "fired on demonstrators", the rebel spokesperson said.
The Libyan's strongman's troops had not yet taken Misrata, but "have taken up position along the main road where they have deployed three tanks, as well as positioning snipers on rooftops," the rebel spokesperson said.