Hassan Shami camp, about 15 miles east of Mosul, is pristine, the gravel spotless, the rows of tents still white and mostly empty.

There aren't yet the crowds of children, piles of garish mattresses, makeshift bathtubs, half-eaten bowls of rice and beans that have become familiar sights at Iraq's many camps for about 2 million people now displaced by the fight against the Islamic State.

That is likely to change, and soon.

Elite counter-terror forces are now nudging into the ISIS-held city of Mosul. Thousands of people are fleeing that fighting, many carrying nothing with them.

Aid agencies fear hundreds of thousands of Mosul residents could follow.

A few hundred arrived at Hassan Shami on Tuesday, running away as Iraq's security forces battled ISIS in the very last villages before the city proper begins.

One woman, Fawzia Akhlef, washes her children's dusty clothes. "We heard fighting, tanks, shelling," she says as she wrings out the little sweatpants and socks.

"We were happy," she said. "We knew it was dangerous, but we just wanted to be under the control of the army."

Waving a white flag

These people are poor farmers and say life under ISIS was bad — not so much because the extremists enforced harsh rules, but because it cut them off from government assistance and because food and fuel prices rose. They were hungry.

Inside a tent, Najm Abdullah and his wife, Hamda Mohammad, tell me they fled the same village.

They don't know a lot about what's been going on in Iraq. Under ISIS, mobile phones and TVs weren't allowed. But Abdullah says they secretly listened to army commanders on the radio.

"They told us not to be afraid of the armed forces," he says. They heard the army was telling people in ISIS areas to wave a white flag when soldiers came.

As the fighting escalated, they fled, driving through crossfire. As they moved further from ISIS and closer to the soldiers, they waved their white flag, and the shooting stopped.

Now they hope there will be a school in the camp for their kids, who have for months been selling water to passing cars because the family got so poor.

When I speak to camp director Ruzgar Obeid, he says when people from ISIS areas arrive, you can tell they're traumatized.

"You can see in their faces, they have psychological problems," he says. "They were in a dangerous situation, they come here and they're safe."

'It's going to be very difficult'

More than two weeks after the fighting began, a relatively small number of civilians have fled the fighting, maybe 18,000, according to aid agencies. Here, east of Mosul, most of the battles so far have taken place in empty villages.

But on Wednesday, special forces began pushing deeper into the heavily populated city. Aid agencies say as many as a million people or even more still live in Mosul, roughly half the population that was there before the Islamic State arrived in 2014.

And Obeid thinks his camp will fill up soon with people running away.

"It's going to be very difficult," he says. He just got word that there are 2,000 people who have fled the fighting today. The army is bringing them to his camp.

Aid agencies and the U.N. have been hustling to build enough camps for the hundreds of thousands of people who could flee the fighting once it reaches the center of Mosul.

ISIS has mounted fierce resistance. Now that some Iraqi forces are moving into the city itself, commanders expect the fight to become even tougher.

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