Kadhafi's latest comments came after his forces pressed rebels in the west on Wednesday and threatened their eastern bastion of Benghazi, despite calls from UN chief Ban Ki-moon for an immediate ceasefire.
"The battle starts today (Wednesday) at Misrata and tomorrow, that will be the decisive battle," Kadhafi was quoted as saying by state television, referring to Libya's third city, which has a population of half a million.
"From this evening, you are going to be called to take up arms and tomorrow you will take part in the battle," he added in an address to a group of young people from Misrata, according to the television report.
Kadhafi urged his audience "not to leave Misrata hostage in the hands of a handful of madmen."
On Tuesday, Libyan state television said the army would soon move against Benghazi, and on Wednesday, Kadhafi's son Seif al-Islam predicted that everything would be over in 48 hours.
A rebel spokesman in Misrata, which lies 150 kilometres (90 miles) from the capital Tripoli, said Wednesday that opposition forces had beaten back an attack by Kadhafi loyalists, but that four people were killed and 10 wounded.
