At least 105 army forces, including 10 officers, killed by the Islamic State in a week of fierce fighting east of Hama and Homs provinces, local activists said.
The Islamic State militants attacked regime forces and their allies on Wednesday around the mountainous Jabal al-Shomariya area in Homs province, and the regime side was carrying out airstrikes.
Clashes between ISIS and regime forces have also erupted Athariya-Rusafa highway near Salamiya town In the eastern countryside of Hama.
Islamic State has been losing ground to regime forces further east, close to its stronghold of Deir al-Zor province and al-Sukhna, the last town it holds in Homs province.
Pro-regime news feeds said about 500 troops have been killed in the last three months in eastern Hama.
Another heavy death toll in regime ranks took place in the Syrian desert as 172 troops have been killed by ISIS since last week, pro-regime news outlets said amid mounting anger among pro-regime areas.
The Syrian Soldier, pro-regime Facebook page with wide network of sources, said more than 700 soldiers have been lost and killed since May in the Syrian desert, also known as al-Badiya, not just by ISIS or rebels but due to lack of water and food.
Pro-regime activists blamed top army officers, saying those who are standing behind the missing of army soldiers. They have been deployed in desert without food supplies or telecommunication devices.
Since May, the Assad army has been conducting a broad military campaign to recapture the vast desert that separates the capital Damascus from Deir al-Zor and other towns along the Euphrates Valley.
Syrian regime has depended on its allied militias mostly from Latakia and Tartus province in Badiya battles where most of them have no war experience.
Retired colonel told Ammar Johmani the summer heat and lack of medicine have also increased the death toll of regime army.
Last week, U.S.-backed Jaish Osoud al-Sharqiya killed 15 regime troops in al-Badiya, when its artillery and Grad rockets pounded an army stronghold in Um Remam area, spokesman Said Seif said.
