The BGM-71 TOW (Tube-launched, Optically-tracked, Wire-guided) missiles are surfacing in Syria as part of a "pilot program" to boost the morale of the downhearted militants, The Times Herald reported on Friday, citing a US official who spoke on condition of anonymity.

The sophisticated missiles are designed to destroy tanks and blow up reinforced bunkers.

The delivery of the deadly weapons began in March and is part of a program that could lead to larger flows of sophisticated weaponry into Syria, said the former official.

"They will try this first and see how it goes" before expanding it, the official added.

Washington’s readiness to arm the militant groups comes following recent advances by Syria’s national army in their battle against the foreign-backed militants.

Syria sank into war in March 2011 when pro-reform protests turned into a massive insurgency following the intervention of Western and regional states.

The unrest, which took in terrorist groups from across Europe, the Middle East and North Africa, has transpired as one of the bloodiest conflicts in recent history.

SHI/SHI