AMIRIYAH AL-FALLUJAH, Iraq — Tens of thousands of Iraqis who survived a harrowing flight from Fallujah now find themselves in sprawling desert camps with little food, water, or shelter.

The growing humanitarian crisis less than an hour’s drive from Baghdad has reinforced the region’s deep-seated distrust of the government and could undermine recent gains against the Islamic State, also known as ISIS.

As Iraqi forces battled their way into the city and Islamic State militants melted away, Khaled Suliman Ahmed fled in a wheelchair, joining hundreds of others fleeing on foot into the desert. When the wheelchair broke down after six miles, his sons and wife carried him, and when they saw the tents, they assumed the nightmare was over.

‘‘I thought we were going to be saved from hell and brought to heaven,’’ Ahmed said, ‘‘but we were surprised by what we found here’’ — a sprawling camp with little food or water, and nowhere near enough tents to shelter tens of thousands of civilians. They joined thousands of people living out in the open, where temperatures approach 120 degrees.

Scores of homes were looted and burned as Fallujah was liberated, which Iraqi forces blamed on the retreating militants. Some provincial police, however, blamed the fires on Shi’ite militia fighters operating with the federal police.

The allegations are on a much smaller scale than those in another Sunni-majority city, Tikrit, after government-sanctioned Shi’ite militias helped retake it from ISIS. The Iraqi government had sought to try to prevent similar abuses in the Fallujah campaign.

Iraqi forces declared Fallujah ‘‘fully liberated’’ on Sunday. The city had been held by ISIS for more than two years and was the group’s last stronghold in the vast Anbar province.

Prime Minister Haider al-Abadi has hailed a string of victories against ISIS in Anbar.

But the government was ill-prepared to deal with the humanitarian crisis unfolding west of Baghdad, where the UN estimates that 85,000 people have fled their homes in the past month.

The conditions in the camps are reinforcing perceptions of a government that is hopelessly corrupt and ineffective. That could fuel unrest in the overwhelmingly Sunni province, which has a history of rebellion against the Shi’ite-led government going back to the 2003 US-led invasion.