The fighters, said to be from the al-Farouq Brigade, said that they launched a series of attacks on Friday on the Syrian government army and gained control of some areas there.
However, the video emerged as opposition activists said at least 35 people had been killed in a renewed Syrian army effort to regain control of Homs province.
The army bombarded opposition strongholds in the city of Homs and the towns of Qusair, Talbiseh and Rastan, the activists said.
Free Syrian Army rebels had been intensifying attacks on army patrols, roadblocks and missile batteries in the area, the Syrian Network for Human Rights and other opposition campaigners said.
In other footage the funeral of nine people took place, who were reportedly killed in the overnight shelling of Ma'arat al-Nouman in Idlib province.
