Militants linked to Islamic State (Isis) have reportedly launched a surprise attack against anti-government opposition forces in Syria, seizing land near Israel and Jordan.

The jihadists crept towards the Golan Heights area of southern Syria, after launching dawn raids on Monday (20 February), backed by armoured vehicles and tanks.

They were said to be aided by sleeper cells and sympathetic locals, catching opposition groups off-guard.

"In a surprise attack, Islamic State [Daesh] made an attack on positions held by the Free Syrian Army [FSA] groups which no one expected to happen so fast," Colonel Ismail Ayoub, a Syrian opposition army defector, said to Reuters.

The terrorist-linked groups took control of Tseel, Sahem al Golan, Adwan and Tel Jamoua.

They also captured Jileen and Heet, but were later driven out of the two villages after a counteroffensive by Southern Front groups, an alliance of FSA factions.

The offensive was reportedly carried out by the Khalid Ibn Al Walid Army, which is an ultra hardline coalition made up of the Yarmouk Martyrs Brigade, the Islamic Muthanna Movement and the Army of Jihad.

The group has pledged allegiance to Isis. It is not clear what precautionary steps Israel took in the wake of the attacks, but terrorist factions have been careful to rattle the Jewish state.

Jordanian security forces told Reuters that army units along the border were put into a state of heightened readiness. Much of the FSA's coordination is also carried out from Jordan, with the assistance of US advisers.

As the terrorists made their offensive, they reportedly executed a number of people. The timing of the offensive has prompted accusations the militants had exploited the preoccupation of the FSA in its battles with the Syrian Arab Army.

Golan Heights
Syrian army soldiers fire during a battle in Syria with militants near the border fence with the Israeli-occupied Golan Heights (file picture). Reuters