In Raqqa, ISIL governs with fear and efficiency
The group known for its beheadings, crucifixions and mass executions provides electricity and water, pays salaries, controls traffic, and runs nearly everything from bakeries and banks to schools, courts and mosques.
While its merciless battlefield tactics and its imposition of its austere vision of Islamic law have won the group headlines, residents say much of its power lies in its efficient and often deeply pragmatic ability to govern.
Syria's eastern province of Raqqa provides the best illustration of their methods. Members hold up the province as an example of life under the Islamic "caliphate" they hope will one day stretch from China to Europe.
In the provincial capital, a dust-blown city that was home to about a quarter of a million people before Syria's three-year-old war began, the group leaves almost no institution or public service outside of its control.
"Let us be honest, they are doing massive institutional work. It is impressive," one activist from Raqqa who now lives in a border town in Turkey said.
In interviews conducted remotely, residents, ISIL fighters and even activists opposed to the group described how it had built up a structure similar to a modern government in less than a year under its chief, Abu Bakr Al Baghdadi.
The group's progress has alarmed regional and Western powers - the UAE on Wednesday called on a clear strategy from the international coumminty to fight ISIL, saying the group "aims to kill, terrorise and displace civilians, ransack property, and demolish historic and religious sites".
The fight against ISIL will take a group effort as it has embedded itself so thoroughly into the fabric of life in places like Raqqa that it will be all but impossible for US aircraft - let alone Iraqi, Syrian and Kurdish troops - to uproot them through force alone.
Last year, Raqqa became the first city to fall to the rebels fighting to overthrow Bashar Al Assad. They called it the "Bride of the Revolution".
A variety of rebel groups ranging from hardline Islamists to religious moderates held sway in the city, although Islamists clearly dominated. Within a year, ISIL had clawed its way into control, mercilessly eliminating rival insurgents.
Activists critical of the group were killed, disappeared, or escaped to Turkey. Alcohol was banned. Shops closed by afternoon and streets were empty by nightfall. Communication with the outside world, including nearby cities and towns, was allowed only through the ISIL media centre.
Those rebels and activists who stayed largely "repented", a process through which they pledge loyalty to Al Baghdadi and are forgiven for their "sins" against the ISIL, and either kept to their homes or joined the group's ranks.
But after the initial crackdown, the group began setting up services and institutions - stating clearly that it intended to stay and use the area as a base.
"We are a state," one commander in the province said. "Things are great here because we are ruling based on God's law."
Some Sunnis who worked for Mr Al Assad's government stayed on after they pledged allegiance to the group.
"The civilians who do not have any political affiliations have adjusted to the presence of ISIL, because people got tired and exhausted, and also, to be honest, because they are doing institutional work in Raqqa," a Raqqa resident opposed to ISIL said.
Since then, the group "has restored and restructured all the institutions that are related to services," including a consumer protection office and the civil judiciary, the resident said.
In the past month alone, ISIL fighters have broadcast images of themselves beheading US journalists James Foley and Steven Sotloff as well as captive Kurdish and Lebanese soldiers, and machine-gunning scores of Syrian prisoners wearing nothing but their underwear.
But the group's use of violence has not been entirely indiscriminate. The group has often traded with businessmen loyal to Mr Al Assad when it has suited its interests, for instance.
According to one fighter, a former Assad employee is now in charge of mills and distributing flour to bakeries in Raqqa. Employees at the Raqqa dam, which provides the city with electricity and water, have remained in their posts.
The group's willingness to use former Assad employees displays a pragmatism residents and activists say has been vital to its success holding onto territory it has captured.
They have been helped by experts who have come from countries including in North Africa and Europe. The man Al Baghdadi appointed to run and develop Raqqa's telecoms, for instance, is a Tunisian with a doctorate in the subject who left Tunisia to join the group.
Reflecting ISIL's assertion that it is a government - rather than simply a militant group that happens to govern - Al Baghdadi has also separated military operations from civilian administration, assigning fighters only as police and soldiers.
Instead, Al Baghdadi has appointed civilian deputies called walis, an Islamic term describing an official similar to a minister, to manage institutions and develop their sectors.
Administrative regions are divided into waliyehs, or provinces, which sometimes align with existing divisions but, as with the case of the recently established Al Furat province, can span national boundaries.
Fighters and employees receive a salary from a department called the Muslim Financial House, which is something like a finance ministry and a bank that aims to reduce poverty.
Fighters receive housing, including in homes confiscated from non-Sunnis or from government employees who fled the area, as well as about US$400 (Dh1,470) to $600 per month, enough to pay for a basic lifestyle.
One fighter said poor families were given money. A widow may receive $100 for herself and for each child she has.
Prices are also kept low. Traders who manipulate prices are punished, warned and shut down if they are caught again.
The group has also imposed Islamic taxes on wealthy traders and families.
"We are only implementing Islam, zakat is an Islamic tax imposed by God," said a militant in Raqqa.
Analysts estimate that ISIL also raises tens of millions of dollars by selling oil from the fields it controls in Syria and Iraq to Turkish and Iraqi businessmen and by collecting ransoms for hostages it has taken.