The Nusra Front, Al Qaeda's official branch in Syria, released footage on Tuesday showing the capture of the town of Naba Al-Sakhr in Quneitra, along the border with Israel.

The video begins showing Nusra fighters advancing after regime soldiers flee their assault, and goes on to show them entering the town and speaking to one of the few remaining residents there.

Watch: Al Qaeda on Israel's border:

It comes as rebel groups, including the Nusra Front, continue to make gains against regime positions along the border, in fierce clashes which have spilled over into Israel territory with increasing frequency.

On Monday, an IDF soldier in the Golan Heights was wounded by stray gunfire from the fighting. And last week, the IDF responded to "errant fire" by regime forces, hitting a Syrian military position after a mortar shell hit the Israeli Golan.

That incident followed several other errant mortar shells falling on Israeli territory, as well as the shooting down of a Syrian drone just 24 hours beforehand after it strayed into Israeli airspace.

Although until now the fire into Israel has been inadvertent spillover, there is concern that some Islamist rebel groups, like the Nusra Front - which frequently talk of "liberating Al Quds (Jerusalem)" - could use such positions to launch attacks on Israel in the future.