FALLUJAH, Iraq — In the three days since the Iraqi city of Fallujah was reopened for residents following its recapture from the Islamic State group, just over 500 families have returned home, Maj. Gen. Saad al-Harbea, the head of west Baghdad operations, said.

Hundreds more have massed around the checkpoints that block the city’s entrance to await the multiple security approvals required to re-enter Fallujah, which lies 40 miles (65 kilometers) west of the Iraqi capital. But the vast majority of the 300,000 people that made up the city’s prewar population remain scattered across the country.

Fallujah was the first Iraqi city to fall to IS, in January 2014. Its civilian population steadily declined after the militant takeover, with some families renting homes in the Iraqi capital, Baghdad, or traveling further north to the country’s semi-autonomous Kurdish region.

Many more civilians were forced out of the city by Iraqi troops as they pushed through Fallujah, leaving a ghost town in their wake. Fallujah was declared “fully liberated” in June, following an operation that officially lasted just over a month and was assisted by U.S.-led airstrikes. The tens of thousands of people who left the city last summer often ended up in desert camps with little food or water.

Al-Harbea defended the security checks outside Fallujah as essential to preventing IS from regaining power in the city. “Of course we need to turn some people away,” he said.

He said Iraqi intelligence agencies had drawn up lists of IS collaborators based on information from local leaders and informants within the extremist group. Ten families had been turned away so far because “they had sons or fathers with connections to Daesh,” he said, using the Arabic acronym for the Islamic State group.

Repopulating territory retaken from IS militants is a slow process, demonstrating how painstaking wider reconciliation efforts will be in Iraq, where suspicions and enmity plague communities long after the fighting stops and victory has been declared.

In Fallujah, the process is rendered more difficult by the town’s history of anti-government sentiment.

After the U.S.-led invasion toppled Iraq’s longstanding leader Saddam Hussein in 2003, many of Fallujah’s residents initially supported the Sunni insurgency that rose up against U.S. forces and the Shiite-dominated government in Baghdad. Militants from al-Qaida in Iraq fought two bloody battles with U.S. troops in Fallujah in 2004, in which more than 100 Americans were killed and over 1,000 wounded.

Inside the city today, little has changed since the aftermath of IS’s overthrow.

Basic services like running water or electricity have not yet returned. Military vehicles line the streets and in many neighborhoods the only signs of life are the freshly-painted checkpoints.

As a military convoy rolled through a narrow residential street, a handful of children peeked out of garden gates. On one street corner a group of men sold cooking gas, and a local mosque handed out large bricks of ice and thin mattresses.

Basaad Jadoua, 58, along with her her daughter, son and husband, had waited for days for security approval to return to the city that has been their family’s home for generations. Squeezed into a microbus between tanks of water and bags of dried food stuffs, they drove along a debris-strewn road, past rows of looted shops, burnt-out government buildings and razed homes. They had brought the essentials with them, they said, because they had heard they were impossible to buy in Fallujah.

The family had fled the city in 2013 when, following two years of instability, it became clear that IS was growing in power. They haven’t returned since.

The bus stopped outside their house, on an empty street flanked on both sides by damaged or destroyed buildings.

“For 30 years this was my home,” Jadoua said, looking over the garden wall.

Unlike many of the city’s residents, her home is still standing, but it had been looted and a rocket that landed in the front garden destroying the driveway where her husband’s car still stood. The windows were all broken and the rooms were filled with dust. Her husband and son busied themselves unloading the minibus and evaluating the damage.

Jadoua faltered as she walked up the driveway and began to cry. Her daughter, Imaa, 24, found an unbroken plastic chair for her to sit on in a room inside, and Jadoua seemed to recover her composure. “We knew there would be destruction, so we were prepared,” she said, “once there is water and electricity, I know we can return to our old lives.”

Associated Press writers Khalid Mohammed and Faris Mohammed in Fallujah, Iraq contributed to this report.