And their numbers are small. Officials in the rebels’ transitional government have provided many different figures, sometimes saying 10,000 or men are under arms in their ranks.

But a small fraction actually appear at the front each day — often only a few hundred. And some of the men appear without guns, or with aged guns that have no magazines or ammunition.

For the nations that have supported the uprising, the state of the rebels’ armed wing — known as the Forces of Free Libya — raises many questions. It seems unlikely that such a force can carry the war westward, through dug-in Qaddafi units toward the stronghold of Surt, much less beyond, toward Tripoli, the Libyan capital. And a sustained war of attrition could quickly bleed their ranks dry.

Unlike many antigovernment militias in other countries, the rebel-armed column has not had the benefit of years of guerrilla fighting, which could have winnowed and seasoned its leaders and given them a skeletal field structure to build on.

Instead, Libya’s rebels have entered the grim work of waging war almost spontaneously, and would need time, training, equipment and leadership to develop into even a reasonably competent force.

For now, their ranks have three elements: a so-called “special forces” detachment of former soldiers and police officers; a main column organized into self-led cells of fighters built around a few weapons and pickup trucks; and a sort of home guard that is undergoing quick training to man checkpoints and serve as a civil defense force.

There is also the “shabab,” milling groups of youngsters who arrive at the front each day hoping to pitch in, but with scant idea of how. Officially, the shabab are not part of the fight.