The group claimed responsibility for explosions that killed dozens of people in Homs.
The head of military security was among the dead after attacks at two Syrian security offices
With the United States now taking a diplomatic back seat, Russia - whose military intervention turned the tide of Syria's war and helped President Bashar al-Assad recapture Aleppo - is potentially a kingmaker.
The U.S. action orders American companies to cut off all ties with the men and freeze any assets.
Rebels said the militants were able to extend their area of control in territory that forms a natural barrier between Syria and Israel where the Yarmouk River flows after they overran the towns of Tseel, Sahem al Golan, Adwan and Tel Jamoua.
Moscow has already ordered more than 10,000 medals for the conflict.
The claim comes as Trump accelerates campaign to defeat the extremist group.
The U.S. conducted the airstrikes near the rebel-held city of Idlib.
The Syrian leader previously said that Trump could be a "natural ally".
Most of those executed are alleged to be civilians opposed to the Syrian regime.
The ministry’s pages are intended to inform Arab speakers on the “humanitarian situation” in Syria.
The ruling was cheered at several major U.S. airports where protesters angry with Trump's order gathered.
The draft executive order awaiting Trump’s signature signaled the new administration was preparing a step that Trump’s predecessor Barack Obama long resisted, fearing the potential for being pulled deeper into the conflict.
The reports have heightened fears that a new era of hostility from the West is dawning.
In Kazakhstan, the rebels have only interacted with the Syrian regime via intermediaries.
Ahead of peace talks, rebels' representative says it's a 'real test of the power of Russia' to hold off Iran and the Syrian government.
The group also destroyed the tetrapylon, a cubic-shaped ancient Roman monument.
Recapturing Raqqa, the "capital" of ISIS's self-declared caliphate, presents a more difficult task.