aid officials have said, as Iraqi forces continued to advance on the most populous city under Islamic State control.
At least 5,000 people, mostly women and children, have arrived at the overcrowded al-Hol refugee camp across the border in Syria over the last 10 days, and 1,000 more are waiting on the border, the charity Save the Children said, citing its workers on the ground.
“These families arrive with nothing but the clothes on their backs and find almost nothing to help them,” said Tarik Kadir, the organisation’s head of Mosul response operations. “The camp is bursting at the seams and risks being overwhelmed. Conditions there are among the worst we’ve seen, and we expect thousands more people to be on their way soon.”
Since the operation began on Monday, more details have emerged of the suffering of civilians in Mosul, where an estimated 5,000-6,000 Isis fighters are based. Residents say the militants are using civilians as human shields and preventing them from fleeing the city.
“Our life was very difficult, every day they killed someone,” said Omar Ali Hussein, 32, who left Mosul with his disabled wife on Tuesday, and is being screened by Iraqi security forces in the town of Qayyarah, a staging ground for the battle. “We were under siege for two days as Daesh deployed snipers.”
Others spoke of Isis militants abandoning their checkpoints and trying to mix with the population.
“There was a checkpoint on our road but today it was not there any more,” a 35-year-old resident of east Mosul told the Guardian. “Around 25 militants have moved in to Shia and Christian empty houses in our neighbourhood this evening, taking up positions in these houses.”
Concerns are mounting over the potential civilian toll of the conflict. The International Committee of the Red Cross said it was prepared even for the potential use of chemical weapons in the campaign.
Isis has deployed mustard gas in recent months in battles against Kurdish peshmerga forces. As many as 200,000 civilians are expected to be displaced in the early weeks of the campaign, in what aid agencies are describing as possibly the largest humanitarian operation around the world this year.
The UN’s refugee agency has set up five camps in the area to hold 45,000 people, and hopes to have a total of 11 camps ready in the coming weeks, which should provide shelter to 120,000 people.
On Wednesday, Iraqi forces advanced further in the area surrounding Mosul and were moving to retake Qaraqosh, a majority Christian town that was conquered by Isis in summer 2014. Its residents were exiled, sparking concern over the future of Christianity in the region.
The Popular Mobilisation Forces (PMF), a conglomerate of Shia militias set up in the aftermath of Isis’s sweep into Iraq, also outlined its role in the battle to retake Mosul, saying it would set up blocking positions to the west of the city in order to confront Isis fighters attempting to flee into Syria. The role would require the PMF leading the effort to take over the town of Tal Afar to the west.
“The PMF will be backing the security forces on the western front ... along two axes. The first is Tal Afar and the second is to support the forces going into the centre of Mosul,” a statement on the PMF website said.
The Shia militias’ participation in the battle has sparked concerns that it could increase sectarian tensions and reprisals. The militias have been implicated in a range of human rights abuses, from forced displacement to arbitrary detentions, in the aftermath of victories against Isis in predominantly Sunni areas.
Sirwan Barzani, a brigadier general of the Iraqi Kurdish peshmerga, told CNN on Tuesday that it could take two weeks for forces advancing on Mosul to reach the city, and two months to liberate it from Isis.