Beirut (AFP) - The jihadist Islamic State has withdrawn from several villages dominated by a Sunni tribe in eastern Deir Ezzor province after clashes, a monitoring group said Friday.

The Syrian Observatory for Human Rights said the extremist group had withdrawn from Abu Hamam, Kashkiyeh and Ghranij, three villages dominated by the Sunni Shaitat tribe in oil-rich Deir Ezzor.

The group said members of the tribe also set fire to a headquarters belonging to the Islamic State in a fourth village and there were reports that the jihadists had withdrawn from a fifth village in the area.

Fighting between members of the Shaitat Sunni tribe and jihadists began on Wednesday, with tribal members tweeting about an "uprising" against IS.

The clashes erupted after IS detained three members of the tribe, "violating an agreement", it said.

The Observatory said the Shaitat had promised IS it would not oppose it, in exchange for the jihadists not harassing or attacking its members.

On Thursday, IS members raided the villages, searching houses and kidnapping or "detaining" an unknown number of people, the Observatory said, adding that fighting was raging.

The Observatory said nine IS fighters had been killed in the clashes, and that the jihadist group was rallying forces from across the border in Iraq to send in as reinforcements.

IS has its roots in Al-Qaeda but has split from the group and has seized large swathes of territory in both Syria and Iraq.

It faces opposition from both moderate and Islamist rebels in Syria.