Kabul, Afghanistan (CNN)The flag is crude, handmade, but the message is clear — allegiance to ISIS in Afghanistan. And the timing — with America withdrawing, the Taliban fractured, young men disillusioned and angry — could not be worse. A group of fighters in Afghanistan agreed to be filmed by a CNN cameraman parading their ISIS flags in a valley not far to the south of Kabul, the Afghan capital. They are the first images of their kind shot by western media inside Afghanistan. The rise of ISIS is an issue that the Afghan President, Ashraf Ghani, has termed a “terrible threat.”