A military and diplomatic source tells Russia’s Sputnik news agency that the terrorists were taken to “safer regions.”

https://uprootedpalestinians.wordpress.com/2018/09/23/us-led-aircraft-evacuate-daesh-commanders-from-eastern-syria-report/
Syria has been gripped by foreign-backed militancy since March 2011. The Syrian government says the Israeli regime and its Western and regional allies are aiding Takfiri terrorist groups that are wreaking havoc in the country.