For a third time in three days Iran has denied repeated Turkish statements that the two countries are cooperating in a military operation against Kurdistan Workers’ Party (PKK).

Samer recalls the gruesome shock of seeing his friend’s headless corpse strung up above Raqqa’s main square.

When the Islamic State raised its black flag over the Syrian city of Raqqa in early 2014, it began its transformation from fringe regional player to fearsome global threat. By the end of that year, it had seized large stretches of territory in Iraq and Syria, creating a rogue state …