Stocks of these missiles have gone missing from arms depot abandoned by forces loyal to Libyan strongman Muammar Gaddafi as the rebels overran large parts of eastern and western Libya.
The first batch of these missiles went missing in the early stages of the Libyan uprising. But the leakage had resumed recently with rebels gains in western Libya, the New York Times reported.
The paper, quoting US officials, said the new range of missiles which have gone missing are also of the shoulder-firing low-altitude surface-to-air missile system which have high explosive warheads.
Broadly comparable to the US Army stringer and FIM-43 Redeye missiles, the SA-7s can be a deadly weapon in the hands of terror groups like al-Qaeda.
The official said that African nations bordering Libya had said that such missiles had been trafficked over Libyan border and could become accessible in black market.
The NYT said signs of the diversion of these missiles were readily visible at an ammunition depot captured last month from the Gaddafi's forces after NATO bombings.
Forty-three empty wooden cases had been left behind on the sands inside the entrance and the missiles were reported missing.
During more than four decade in power, Gaddafi's government is thought to have acquired as many as 20,000 of these missiles, known as Manpads, for Man-Portable Air-Defence System in the former Eastern bloc.