Sochi, Russia- President Vladimir Putin said on Thursday that Daesh militants had seized nearly 700 hostages in part of Syria controlled by US-backed forces and had executed some of them and promised to kill more.

Speaking in the Black Sea resort city of Sochi, Putin said the hostages included several US and European nationals, adding that Daesh was expanding its control in territory on the left bank of the River Euphrates controlled by US and US-backed forces.

Putin did not specify what the militants’ demands were.

“They have issued ultimatums, specific demands and warned that if these ultimatums are not met they will execute 10 people every day. The day before yesterday they executed 10 people,” Putin told the Valdai discussion forum in Sochi.

The TASS news agency reported on Wednesday that Daesh militants had taken around 700 hostages in Syria’s Deir Al Zor province after attacking a refugee camp in an area controlled by US-backed forces on October 13.

TASS said the militants had kidnapped around 130 families and taken them to the city of Hajin.

Putin also hailed Turkey’s efforts to set up a demilitarised zone in Syria’s northern province of Idlib.

Putin said Thursday that even though the October 15 deadline for the withdrawal of Syrian radical groups and heavy weapons from the zone hasn’t been fully met, Russia sees that Turkey is doing its best to accomplish the task.

The Turkey-Russia deal reached last month calls for the removal of all members of Syrian radical groups and heavy weapons from the 15-20km deep demilitarised zone in Idlib.

He said that “Turkish partners are doing all they can to fulfill their obligations.” He added that Turkey has been acting “in a tough and efficient way” to enforce the deal.