Tripoli/Washington: After four nights of missile and airstrikes on his military, Muammar Gaddafi's forces marched with their assault towards towns of Misruta, Ajdabiya and Zintan as US President warned that the Libyan ruler may try to ‘hunker down and wait it out’.

The relentless allied attacks may have grounded or destroyed his warplanes and forced his forces back to Benghazi. But, his tanks and heavy artillery laid a siege on the embattled Misruta, the sole city held by the rebels in western Libya, and heavy shelling by his forces left more than 50 people, including children, dead.

Intense fighting also raged for the town of Zintan where the rebel forces were repeatedly thrown back by government troops.

Gaddafi, in his first public appearance since allied strikes, in a live television broadcast "We will prefer to die like martyrs. We will defeat them by any means....We are ready for a fight, whether it is short or a long one.....We will emerge victorious at the end."

He urged all Islamic armies to join him. A television channel said that the siege by Gaddafi's forces of Misruta had almost entered the fourth week and the situation in the city was turning grim with shortage of food, water and medicines.

The Arab channel said that a similar situation prevailed in the eastern city of Ajdabiya, where neither side appeared to be making any breakthrough.

Report said that rebels were taking shelter in sand dunes to hide from the tank fire and were without heavy weapons, leadership, communications or even battle plans.

The allies, though subjecting Gaddafi's military command and control centers to ceaseless bombardments, are reluctant to commit ground troops or even Special Forces to help and guide the rebels.

They have also not so far responded to calls for airstrikes by rebels to help them overrun Ajdabiya and push back the pressure on Misruta.