In 2014, as life in the Islamic State (ISIS) began to stabilize, many of its foreign fighters adopted an almost civilian routine. They spent their time reading, discussing religion, and giving lectures on their visions of a utopian Islamist state. But not all of these fighters’ ideas matched ISIS’ official positions. Many began to disagree with the group’s interpretation of Islam.

Even by ISIS’ standards, these dissidents were extreme. They denounced some of their leaders and fellow militants as kaffirs, or infidels—in ISIS’ thinking, a charge that merits death. By doing so, several thousand fighters turned ISIS’ strongest weapon—its ideology—against the organization itself.

ISIS’ leadership responded to the ultra-extremists with force, killing many of them. But a small number managed to escape and are now in hiding outside of the Middle East.


The story of ISIS’ radical breakaways began when some of its fighters started to turn to the ideas of Ahmad al-Hazimi, a preacher who wrote a book called Ignorance Is Not an Excuse in Islam. Hazimi believes that those who excuse the religiously ignorant and fail to excommunicate Muslims who merit such treatment are themselves kaffirs. (To excommunicate is to declare takfir; the extension of excommunication Hazimi supports is known as “chain takfir.”) Like some other radical groups, ISIS holds that infidels are legitimate targets for killing, but unlike Hazimi’s followers, it does not support chain takfir.

When Hazimi’s followers were fighting in Iraq and Syria, some of them argued that locals who had used government courts and participated in elections were infidels deserving of excommunication. For the most part, ISIS paid them little heed. “How could it be a caliphate if the local people do not even know how to pray?” one ex-fighter from Central Asia asked us in 2016.

The main problem for ISIS was that, taken to its natural conclusion, this logic would eventually lead to the excommunication of ISIS leader Abu Bakr al-Baghdadi himself. “I left my jamaat [group] because my emir [leader] was ignorant and not on the right religious path,” explained the ex-fighter from Central Asia. “But I could not believe that al-Baghdadi was simply not aware of it,” he said. That was a suggestion that Baghdadi was a kaffir as well.

What is more, the ultra-extremists tended to put ideology ahead of political necessity. For example, one of ISIS’ sheiks, Abu Umar al-Kuwaiti, declared the group’s leadership infidels because they refused to destroy the grave of a Sufi sheik in Raqqa. (Kuwaiti was later executed by ISIS.) Other takfiris disagree with ISIS fighters’ practice of volunteering for suicide missions in the name of religion. Those fighters “do bad things,” a foreign ex-fighter told us, “but they think they will get to heaven because they are willing to kill themselves. That is not Islam.”

ISIS leader Abu Bakr al-Baghdadi in Mosul, July 2014.
Social Media Website via Reuters TV / REUTERS

Nor was this all. Some takfiris rejected ISIS’ propaganda. They argued that when foreigners with poor Arabic skills listened to nasheeds (ISIS songs sung a cappella), they could not understand the words and so listened to the rhythm. That made nasheeds into music—which they believed was prohibited. The ex-fighter from Central Asia told us that he refused to fight under ISIS’ flag because he did not consider it Islamic. “A true Islamic flag should only have the [first part of the] shahada [there is no God but Allah] written on it,” he explained. “Not a circle with ‘Muhammad is his messenger.’”

Others disagreed with ISIS’ use of visual signals to distinguish Muslims from non-Muslims. “When others see a man with a beard, long hair, and wearing traditional clothes, they think that he is a Muslim,” an ex-fighter told us in September. “For me, it does not mean anything: by default, I consider him non-Muslim, before he proves otherwise by his deeds.”

Most of the ultra-extremists were foreigners, and a number came from Tunisia and the former states of the Soviet Union. They had made a dangerous trip to Syria to fight and die for Islam. If they believed that their group’s leadership were infidels, little could stop them from standing up to the organization, even if it would cost them their lives.


By 2015, the takfiris’ dissatisfaction with their group’s policies and leadership had grown. Some, hoping to realize their own vision for the caliphate, started trying to change the system from within. Many volunteered for the hisbah—the religious police in charge of enforcing sharia. But their attempts to impose piety were frustrated. Some members of the hisbah arrested people for supposed crimes, only to have local judges let them go. “We were fighting and dying to live in the Islamic State,” one ex-fighter complained, “and the locals not only did not care about sharia law but also wanted us to not bother them with it.” So some fighters started to punish violations of sharia outside of official avenues. For example, they would beat or kill cigarette smugglers instead of bringing them to ISIS’ police stations.

 ISIS could not tolerate the dissent within its ranks. It started to crack down on the takfiris. The ultra-extremists scattered. Some tried to hide in the caliphate’s periphery, volunteering to fight against Iraqi forces in Mosul or retiring from combat and moving closer to the Turkish border. Others tried to obscure their beliefs: they would attend mandatory prayers in the mosques, an ex-fighter from Dagestan told us, and then redo their prayers at home. But many practices were not so easy to hide. Unlike other fighters, takfiris would fast twice a week, and they would pray seven times each day instead of the usual five.

ISIS arrested, jailed, and executed those who could not escape. “We first learned about this from rumors,” the ex-fighter from Dagestan said. “Some women began to receive notices that their husbands had been executed for being disbelievers. The number rose to thousands.” As the group’s ranks thinned, some of the takfiris went on suicide missions.

In prison, ISIS guards developed informal tests to determine which prisoners were takfiris, said an ex-fighter who spent five months in an ISIS prison on charges of disbelief. For instance, guards would watch to see whether prisoners would eat the chicken they were given for dinner on their first night in detention. Refusing to eat could reveal that the inmate was a takfiri who believed that the cook was a kaffir. The group’s enforcers would also humiliate takfiris by using their piety against them. Another former prisoner told us that guards taunted him for reciting the shahada during a mock execution, and some of the jailed takfiris were not allowed to pray.

After an airstrike in Raqqa, Syria, August 2017. 
Zohra Bensemra / REUTERS

Some prisoners asked their minders basic questions about Islam—a last-ditch attempt to save themselves. By feigning ignorance about the religion, the thinking ran, they could suggest that they were simply misguided and would accept ISIS’ interpretation of the faith if it was explained properly.

Driven by the arrests, the instability in the caliphate grew. To calm its ranks, ISIS turned to propaganda. In 2015, the organization made a video in which a group of Azerbaijani ISIS members confessed that they considered ISIS unbelieving because it did not declare takfir on locals and admitted that they had conspired to attack the group’s leadership. The men were then killed.

This move was counterproductive, sending the tension between ISIS’ leadership and its population (including the takfiris) to dangerous levels. Several ex-fighters said that the takfiris began to step up their attacks on members of ISIS’ internal security forces. “Some Uzbeks from my group wanted to radically oppose the ISIS leadership,” recalled the ex-fighter from Dagestan. “I suggested they wait and get out of Syria first, and then decide who is to blame.”


Because takfiris have spent time within ISIS and understand the group’s supporters, they are effective at dissuading people from sympathizing with ISIS, even as they push those people to a more radical understanding of Islam. “Governments do not understand that we’ve stopped more people from joining ISIS than they have,” one ex-ISIS member told us in September, after moderators on the Russian social network VK removed audio and text files from an online takfiri group page. (Several prominent takfiri lecturers are wanted by their governments on charges of religious extremism.)

The takfiris’ dogmatism has made it hard for them to organize into a united force. Minor disputes—over, for instance, how to properly trim a beard—can escalate into serious religious disagreements and declarations of takfir. What is more, the spats set off chain reactions, as some declare takfir on those who failed to excommunicate the transgressors.

Occasionally, the ultra-extremists shift their loyalty to new religious leaders. Many of Hazimi’s former followers, for instance, have declared him and his followers infidels and now adhere to the teachings of a figure named Hilmi Hashimi. (One ex-fighter we spoke to in October had already declared takfir on Hashimi for having appeared for a hearing in a government court in Egypt.)

Religious radicalism is not dangerous in itself: many of the world’s most extreme believers are quietists. But the takfiris’ experience with ISIS has given them combat training. So far, there have been no known instances of them conducting terrorist attacks or joining new militant groups. But if they decided to once again take up arms, they would be far more radical than ISIS ever was.

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