A few weeks ago Khazir was little more than a name on a map and a checkpoint marking the line between the official territories of the Kurdistan Regional Government (KRG) in Erbil province, and their areas of influence inside Ninawa. With the takeover of Mosul and much of the province by the Islamic State of Iraq and Syria (ISIS, now the Islamic State or IS), the border post has taken on much more significance, as the Kurds try to define who will and who will not be part of their future state.

On the Ninawa side of the checkpoint a new camp is growing. The crest of a low hill alongside the highway, yellow with wheat stubble and dust, now bears a huddle of tents. Blue and white before, they are turning the colour of the ground as the dust settles on them, borne on a wind that gives no relief from the heat. Below the tents, cars are parked close together with canvases stretched between them. Closer inspection reveals families sheltering from the sun underneath. Around two thousand people are thought to be here.

The camp doesn’t yet have a perimeter fence. There is water, but not enough, and latrines, but not enough. Shallow ditches have been dug along the contour lines to take away wastewater, but they are already full of discarded plastic bottles as the residents, especially the children, don’t bother to put them in the bins. Neither the Kurdish authorities, nor the relief agencies, nor the refugees themselves have any real idea of how long the camp will last. The lack of a fence worries people, but at $70 per metre in materials alone it’s impossible to know whether it will be worth it.

The people at Khazir all want to be somewhere else. Most are trying to cross into Kurdistan, but with the Kurds being careful about who they let in, for most it’s an uncertain wait. The Kurdish authorities now require a sponsor within Kurdistan for people arriving from other areas of Iraq. Practically this means it is much easier for those with links to the region – mainly Kurds and Christians – to come in. For Arabs, it’s much harder.

We spoke to several children who had come with their families from Tel Afar, west of Mosul. They told us that, like in many areas attacked by IS, the local police had melted away; and they had driven here to try to get into the Kurdish region. The children were ethnic Turkmen, a group that has suffered attacks by Islamist factions before and so has every reason to fear IS. However, as non-Kurds their chances of being allowed into the KRG area are slim.

The border is marked by a low earth beam, several concrete blast shields and a few guard towers. Trucks coming out of the Kurdistan Region of Iraq (KR-I) pass freely; they bring water and supplies for the refugees and the Peshmerga. The line of vehicles waiting to enter Kurdistan is long and almost stationary; at the front, border guards and desperate, tired, hot people confront each other. One guard threatens to deflate the tires of cars that don’t keep to the right areas – but where the right area is isn’t clear. Voices are raised and the guards assume a more menacing attitude. Cars with Erbil plates pass fairly easily, those with Ninawa ones have a harder time.

Beside the tarmac, families squat on the ground and wait. A water tanker brings some relief from the heat, as people douse themselves with its hoses and women and children rest in its shade. Passing the border, the question all the border guards ask is whether we have any cold water to spare them.

As the Kurdish authorities feel statehood moving closer, the task of defining whom an independent Kurdistan will and will not include is a more pressing task for the leadership. At Khazir, the price of Kurdistan’s future feels like it is being paid by the uncertainty of Arabs and Turkmens, who fear IS but cannot offer the KRG the loyalty of their blood.