Al-Nusra, ISIL clash in east Syria

Heavy clashes have broken out between two major foreign-backed Takfiri groups, al-Nusra Front and the so-called Islamic State of Iraq and the Levant (ISIL), in the oil-rich province of Deir Ezzor in eastern Syria.

The al-Qaeda-linked al-Nusra front has accused the ISIL of attacking its bases in Deir Ezzor, occupying several towns and villages.

The ISIL has besieged Deir Ezzor to kill al-Nusra leader Abu Mohammad al-Julani who has reportedly taken refuge in the area.

Last month, the so-called Syrian Observatory for Human Rights said infighting among extremist militants operating in Syria had left around 3,300 casualties since January.

A British defense study published last September showed that about 100,000 militants, fragmented into 1,000 groups, were fighting in Syria against its government and people.

Foreign-sponsored Takfiri groups have been behind many of the deadly bomb attacks targeting both civilians and government institutions across the Arab country over the past three years.

Syria has been gripped by deadly violence since March 2011. Reports say some 140,000 people have so far been killed and millions of others displaced because of the foreign-backed crisis.