Nusra Front, al Qaeda's Syrian affiliate, has attacked the base of Jamal Maarouf, a well known civilian commander of the U.S. backed Syrian rebels fighting against the Islamic State militants. The attack by the militants, who used tanks, mortars and Chechen snipers , forced Marouf and his group to escape to the Jebal al Zawiya mountains of northern Syria, according to media reports..

The attack assumes more significance as the Nusra Front fighters were supported by the Islamic State militants in the attack on the village of Deir Sinbul.

Though the Nusra Front supports the fight against the Assad regime, it is not an ally of the Islamic State. If the two groups come together, it would have drastic consequences on the war in Syria.

The ouster of Maarouf, who had led the offensive against the Islamic State in January to expel them from two northern provinces, is a major setback for the rebel fighters as well as the U.S. led coalition.

According to the monitoring group Syrian Observatory for Human Rights, the Islamic State militants came from the east of Syria to join the Nusra Front to fight against Maarouf's Syria Revolutionary Front, reports McClatchyDC.

Mahmoud al Ugal, a commander in Marouf's group, said that the militants deployed 20 heavy machine guns apart from the tanks and mortars.

Meanwhile, the Iraqi Kurdish Peshmerga fighters and fellow Syrian Kurds attacked the Islamic State positions in Kobani on Monday, reports Reuters.

Around 150 Iraqi Peshmerga fighters crossed into Kobani through the Turkish border on Friday to help the Syrian Kurds defend the border town of Kobani from the Islamic State onslaught.

Ersin Caksu, a journalist inside Kobani, said that the Peshmerga fighters were supporting the Syrian Kurdish forces with artillery and mortar fire, reports Reuters.