The western Libyan city of Misrata has been besieged for days now and it has become one of the front lines between the rebels and forces loyal to Muammar Gaddafi.
Constantly under attack despite a government-announced but non-existent ceasefire, rebels were filming when a major explosion rocked the city centre.
Gaddafi forces said they had now taken back the city after intense fighting claimed the lives of nine locals but other reports said the rebels still control the centre.
A second besieged city, Zintan, has been under heavy shelling for three days.
But one Swiss journalist said rebels had managed to rebuff government troops.
Meanwhile rebels have been trying to take advantage of the coalition air strikes by advancing down the coastal highway, establishing another front line near Ajdabiya. But a government force attack soon turned them back.
Analysts speculate the uprising could grind to a stalemate with neither side able to make significant gains but rebels say they will still march on Tripoli no matter what.