BEIRUT (AFP) - Jihadists fighting in Syria's war put to use for the first time on Sunday American-made Humvees that they seized during a lightening offensive in Iraq this month, a monitor said.

The Islamic State in Iraq and the Levant, or ISIL, used the armoured vehicles to capture the villages of Eksar and Maalal in Aleppo province, which borders Turkey, said the Syrian Observatory for Human Rights.

It came after heavy fighting against the Islamic Front and its Al-Qaeda-affiliated ally, the Al-Nusra Front, said the Observatory, a Britain-based group that gets its information from a network of sources on the ground.

The two villages are located near the town of Azaz, which ISIL militiamen abandoned at the end of February under attack from rebels fighting to oust Syria's President Bashar al-Assad.

ISIL, which espouses a radical interpretation of Islam and aims to set up a state stretching across the Syria-Iraq border, is now expected to launch a bid to retake Azaz.

ISIL seized the Humvees and sent them to Syria after Iraqi soldiers abandoned them during a surprise Sunni jihadist offensive that claimed Iraq's second city of Mosul and swathes of other territory in mid-June.

Also on Sunday, ISIL gunmen abducted 20 Kurdish students on the road between Hasakeh and Qamishli in northeastern Syria, said the Observatory.

It comes three weeks after ISIL kidnapped 145 Kurdish students in Aleppo, as well as 193 Kurdish civilians at Qabasine village in the same province.

Parents of five students who managed to escape said the jihadists demanded that they join them in the fighting.

Kurdish militias, who are also trying to expand their autonomous region, have fought for months with ISIL, which has been seeking to seize from their control oil fields in northern and eastern areas.