Qaddafi reportedly supporting the troops storm the rebel who came from the south, east, and west of the city.
Misrata suffered severe bombing until mid-May when troops Qaddafi expelled rebel supporters.
The latest fighting occurred while NATO's increased operations in Libya, to ask the world to prepare the post-Qaddafi.
Earlier rebel spokesman told Reuters news agency that the government is doing a new operation against Misrata.
Quoted from the BBC Indonesia, Wednesday explosion heard up to the east of the town when government forces fired Grad rockets back a rebel attack.
Rebel forces told the BBC's David Loyn in Misrata that they have removed the front line east to the coastal town Tawargha.
Twelve insurgents were reported killed in the east, the other two were killed in the western part. Doctors said 24 people were injured.
Ambulances carrying the wounded to be treated. Jammed streets around the hospital while the citizens tried to donate Misrata blood, our correspondent says.
Commander of the southern Salahuddin reportedly injured after a previous Badi Badi seen speaking with a bloody face.