The fate of 15 officers and members of the Syrian regime forces remains unknown, after losing contact with them on Friday during an ISIS surprise attack on al-Rahjan and Shakouziyya in eastern Hama.
The soldiers were traveling on a bus, which was later found burned, and it remains unclear whether ISIS killed or captured them.
The Syrian Observatory for Human Rights (SOHR) had indicated that Russian warplanes carried out more than 170 airstrikes.
However, the strikes subsided after 72 hours, as the regime forces and loyal militias combed the area searching for ISIS cells in the region.
Over the past few days, the terrorist cells inflicted great losses on the regime forces in the area through ambushes and explosions.
SOHR documented the death of seven members of the regime-backed National Defense militia, and the injury of others, during clashes with cells affiliated with ISIS in al-Shoula in western Deir Ezzor desert.
The Observatory indicated that the soldiers were killed during a combing operation, warning that the death toll is expected to increase, as some of the injuries are serious.
It documented casualties on both sides as a result of shelling and clashes within 48 hours of the terrorist attack, between Friday and Sunday.
In addition, 19 members of the regime forces and loyal militants were killed, while 12 ISIS members were killed.
Since the beginning of 2021, the Observatory documented the death of 44 regime officers, soldiers, and loyalists in ambushes, explosions, and attacks by ISIS members in the desert.
Most of the fatalities were in the eastern desert of Hama, while the rest were in Deir Ezzor desert. The military operations also left tens of soldiers injured.
Three civilians, including a little girl, were killed in an ambush on Damascus-al-Raqqah highway.
At least 25 ISIS militants were killed during Russian airstrikes and clashes during the same period.
Meanwhile, the regime forces and loyal militias were unable to hinder ISIS resurgence, despite renewed operations backed by Russia.
SOHR documented over 400 airstrikes by Russian warplanes on the Syrian desert since the beginning of 2021.