Syrian activists and the Islamic State group say the militants have seized a district previously held by Syrian troops in the eastern city of Deir el-Zour.

The industrial district of Deir el-Zour fell to the group late Wednesday following an attack and fierce clashes between the two sides.

The IS-affiliated Aamaq news agency said Thursday that the group began its attack on the district with three successive suicide operations that struck Syrian army outposts inside.

The Britain-based Syrian Observatory for Human Rights also reported the IS capture of the district.

The city in the country's east is held mostly by IS but Syrian troops control a few districts inside and the Deir el-Zour airport on the outskirts of the city.