IS now controls scattered pockets in the eastern countryside of Homs province, the southeastern desert of Deir al-Zour province, an area on the eastern bank of the Euphrates River and a pocket in the northern countryside of Deir al-Zour in eastern Syria.
IS also controls pockets in the Yarmouk area in the countryside of the southern province of Daraa as well as pockets in the southern countryside of Hasakah province in northern Syria.
Despite losing areas measuring tens of thousands of kilometers, IS continues to shade blood in Syria, said the Observatory, adding that the group carried out executions of civilians and rival fighters over the past two months.
IS was recently defeated in southern Damascus when the Syrian army captured its latest strongholds in the Hajar al-Aswad and Yarmouk Camp.
The SDF has also recently launched an offensive on IS east of Euphrates, but the Observatory said the SDF failed to storm Hajin area, the last IS stronghold east of Euphrates and moved the military operation to the southern countryside of Hasakah.
The Syrian army said it had foiled an attack last Wednesday by the IS group on a Syrian military site in Deir al-Zour, killing 43 IS militants, while four Russian experts were also killed in the showdown.
The Observatory, which says it relies on a network of activists on the ground, said intense battles raged between the Syrian army and IS in the countryside of Deir al-Zour, as the terror-designated group has attempted to distract the army by waging sudden attacks.
