The so-called Syrian Observatory for Human Rights said on Monday that one of the Takfiri leaders identified as Amer al-Rafdan was killed in an airstrike in the eastern Syrian province of Deir Ezzor.
Another Takfiri leader identified as Abu Osama al-Iraqi was killed in the northeastern Syrian province of Hasakah.
It is not known whether the terrorists were killed in the airstrikes by Syrian war planes or jets belonging to the so-called US-lead international coalition allegedly fighting the terrorists in Syria without the authorization of Damascus.
The development comes as the Syrian forces are conducting operations against the Takfiri terrorists across the country.