The opposition-linked monitoring group also said the clashes between al-Qaeda affiliate al-Nusra Front and the rival Islamic State of Iraq and the Levant (ISIL) had killed 230 militants in the last 10 days.

Of those, 146 were members of al-Nusra Front and other militant brigades, including some who were executed by ISIL.

The clashes between the two groups in the oil-rich province began at the end of April and come after a wider backlash against the ISIL terrorist gang that started in January.

ISIL, which grew from al-Qaeda's Iraq branch, has been the target of a joint campaign by different opposition insurgents as well as al-Nusra terror group since early January.

The campaign has pushed it out of much of Aleppo and Idlib provinces, though it has strengthened its presence in the provincial capital of Raqa province.

In February, ISIL withdrew from most of Deir Ezzor under pressure, but in recent weeks it has advanced once again, regaining territory in the west of the province.

A recent British defense study showed that nearly 100,000 insurgents, fragmented into 1,000 groups, are fighting in Syria against the government and people.

Syria has been gripped by deadly unrest since 2011. According to reports, Western powers and their regional allies - especially Qatar, Saudi Arabia, and Turkey - are supporting the armed insurgents operating inside the country.

RA/MB