BEIRUT (Reuters) - The Lebanese army found a surface-to-air missile (SAM) in a weapons cache left by Nusra Front militants after it took over some of the jihadists’ positions in northeast Lebanon, a Lebanese security source said on Friday.

The cache also included U.S.-made so-called TOW anti-tank missiles, the source said. Photographs of the cache sent by the security source showed large numbers of shells and rockets.

There have been sporadic reports throughout Syria’s six-year-old civil war of rebel groups gaining access to SAMs. Last year the Syrian government said rebels had used one to shoot down a jet, but insurgents said they had downed it with anti-aircraft guns.

The Nusra Front was the official branch of al Qaeda in Syria until it changed its name a year ago and broke formal allegiance to the global jihadist network.

It held a pocket of territory straddling the border between Syria and Lebanon until a Hezbollah offensive last month that forced it to accept evacuation to a rebel-held part of Syria.

Lebanon’s army has taken over the positions that Hezbollah, a Lebanese Shi’ite group allied to the Syrian government, took from the Nusra fighters last month.

The Lebanese army is also preparing for an offensive against the last militant presence in the mountainous border area, an Islamic State pocket near to the one previously held by Nusra.