GA’A, Libya — Five months after the armed uprising erupted in Libya, a new round of portable antiaircraft missiles — weapons that governments fear could be obtained by terrorists and then fired at civilian jetliners — have been slipping from storage bunkers captured by rebels.

In February, in the early stages of the uprising, large numbers of the missiles slipped from the hands of Col. Muammar el-Qaddafi’s government as the rebels established control over eastern Libya and the ammunition depots there. The leakage resumed recently with rebel gains here in the western mountains, which opened up new ammunition stores.

The new leakage of the missiles, which are of the same type that officials in other African nations have said have already been trafficked over Libya’s borders, underscores the organizational weakness of the forces opposed to Colonel Qaddafi; it also raises concerns that if more Qaddafi depots fall to the rebels, then further stocks of the weapons could become accessible to black markets.

Signs of the diversion are readily visible here, at an ammunition depot captured late last month from the Qaddafi forces after repeated NATO bombings.