Misurata, a lone major rebel outpost in the west of the country, has been under siege by Gaddafi's forces for weeks.
On Friday, rebels said they had pushed back an assault on the eastern flank of the coastal city after fierce street battles.
A Misurata resident called Ghassan told Reuters: "Medics at the hospital told us that five people were killed today and 10 others were wounded. We were at the hospital and we talked to medics."
A rebel spokesman said government troops had advanced on the heavily populated Esqeer district in an effort to loosen the rebels' grip on Misurata, where families are crammed together in the few remaining safe districts.
"The attack from the east has been repelled now and the (pro-Gaddafi) forces have been pushed back," rebel spokesman Hassan al-Misrati told Reuters by telephone.
Rebels say people in Misurata are crammed five families to a house in the few safe districts, to escape weeks of sniper, mortar and rocket fire. There are severe shortages of food, water and medical supplies and hospitals are overflowing.
NATO air strikes hit weapons depots belonging to Gaddafi's forces near the town of Zintan on Friday, a resident said.
"The depots are situated 15 km southeast of Zintan. We could see buildings on fire in the distance," the resident, called Abdulrahman, said by phone.
The only active front in the war, along the Mediterranean coast around the eastern towns of Brega and Ajdabiyah, has descended into a desultory stalemate with both sides making advances and then retreating behind secure lines.
On Friday, rebels at the western boundary of Ajdabiyah, still jittery after the friendly fire accident, fled from an artillery bombardment but there was no sign of a government advance.