On August 28 this year, a Libyan fighter entered the Cordoba Mosque in Sirte, recently liberated from the Islamic State, and issued the call to worship. The young man’s unit, a well-equipped outfit known as the 604th Infantry Battalion, was unlike the hundreds of other armed groups loosely linked to the Tripoli-based Presidency Council that had imposed a months-long siege against the Islamic State’s Mediterranean stronghold. And the battalion’s arrival that day in the cavernous, white-walled Cordoba Mosque carried a unique and emotional significance for its members.

Starting in early 2015, Cordoba’s imam, a popular Salafi cleric named Khalid bin Rajab al-Firjani publicly criticized the Islamic State and refused it permission to use his mosque for sermons. That summer, the Islamic State assassinated him, prompting an armed uprising by residents in Sirte’s Neighborhood Three, drawn mostly from members of the cleric’s Firjan tribe. It failed. The Islamic State sent armored vehicles into the streets and used heavy weapons to subdue the revolt, executing dozens of Firjan in the courtyard of the Cordoba Mosque, and crucifying others on steel scaffolding at the now-infamous Zafran Roundabout. It renamed the Cordoba Mosque the Abu Musab al-Zarqawi Mosque.

In the following months, some Firjan fighters fled from Sirte to Tripoli, where the brother of the deceased cleric had established the 604th Infantry Battalion. With the support of powerful Tripoli-based Salafi commanders, mainly Abdelraouf Kara and his Special Deterrence Force based at Matiga Airport and the nearby Bab Tajura Battalion, it started military training at a camp in Ayn Zara and a coastal nature reserve. By the end of 2015 it had grown to over 450 members.

Then in May of this year, the 604th Infantry Battalion got its chance for payback. It joined a vast coalition of armed groups called Al-Bunyan al-Marsus, or the Solid Foundation, in attacking Sirte. In contrast to other armed units drawn primarily from Misrata, the 604th Infantry Battalion also includes fighters from Sirte, Bani Walid, Tripoli, Zintan, Zliten, and Sabha.

But most importantly, the battalion is almost exclusively Salafi. It is part of a broader nationwide trend among so-called “quietist” Salafists who are now increasingly active as combatants against the Islamic State, but also against rival Islamist factions.

A Doctrine of Obedience From Saudi Arabia

The quietist label in Libya refers primarily to followers of the Saudi cleric Rabia bin Hadi al-Madkhali who promotes a doctrine of obedience to a sitting political authority (wali al-amr), eschewing electoral activism or armed resistance, even in the face of secular rule or tyranny for fear of causing fitna (strife). The Saudi government used his teachings domestically in the 1990s to discredit the popular, Muslim Brotherhood-infused Salafi Sahwa (or Awakening) Movement. Today, Madkhali remains a virulent foe of the Muslim Brotherhood as well as Salafi-jihadi groups such as Al-Qaeda and the Islamic State.

In Libya, the quietist strain has a pedigree stretching back to the mid-2000s, when the Qaddafi regime invited Saudi “establishment” Salafi clerics into Libya as part of its broader efforts at rehabilitating Salafist-jihadists in the Libyan Islamic Fighting Group. After the outbreak of revolution in 2011 Madkhali issued a directive urging non-support, and many of his followers remained loyal to the regime or stayed on the sidelines, although some did eventually join in Tripoli’s August 20 uprising.

After the fall of Qaddafi, the followers of Madkhali in Libya, known as Madkhalis (although they reject the term) demolished Libya’s Sufi heritage and burned Muslim Brotherhood literature. They also formed anti-vice patrols that focused on combatting narcotics trafficking, consumption of alcohol, and other activities they deemed un-Islamic, exemplified most notably by Kara’s Special Deterrence Force and associated groups. With the outbreak of conflict between Libya’s Dignity and Dawn camps in summer 2014, Madakhli armed groups attached themselves to the warring factions. Today, they continue to fight alongside Khalifa Haftar’s Libyan National Army in the east, as well as the constellation of armed groups allied with the Tripoli-based Presidency Council.

But interviews in Tripoli, Misrata, Sirte, Benghazi, and Bayda from late 2015 to mid-2016 reveal deep unease among the Madakhlis’ allies in both the east and west—whether Libyan National Army officers or Misratan field commanders (both uniformed and civilian), or Ministry of Interior officials on both sides—at the current’s growing power and ulterior objectives. It is a suspicion rooted partly in reports of Saudi and Gulf funding, but also Madkhali’s public statements on Libya, which are sometimes contradictory and which many in Libya resent as unwarranted meddling in the country’s domestic affairs.

Positioning For Influence in Sirte

In the west, some Misratan commanders in the Al-Bunyan al-Marsus coalition are uneasy with the 604th Infantry Battalion’s antipathy toward other Islamist-leaning units fighting against the Islamic State in Sirte, especially armed groups affiliated with the Muslim Brotherhood and Libya’s Tripoli-based mufti, Sadiq al-Ghariani, whom Madkhali recently urged his followers to confront. There are also questions about the Madkhalis’ goals in Sirte after the Islamic State is evicted, and their possible intent to dominate its religious and policing institutions.

“We don’t trust them,” one Misratan police officer in the Al-Bunyan al-Marsus coalition told me this summer. “They are trying to infiltrate Sirte’s police just like Ansar al-Sharia did with the security committees,” he added, referring to the Libyan Salafi-jihadi group that has been designated a terrorist organization by the United Nations and the United States.

Some of this distrust, however, is not solely religious, but rooted in Sirte’s complex tribal rivalries, specifically fears by Sirtawi families of Misratan origin, the Maadan, at dominance by the Firjan and Warfalla, whose Salafi members fill the ranks of the 604th Infantry Battalion. It was these local tribal rivalries that partly allowed the Islamic State to rise in Sirte in the first place, and that thwarted any coherent resistance against the terrorist group.

Other sources of friction with the quietist Salafists include their ambivalent or even supportive attitude toward Haftar and his campaign in the east.

“Haftar has the fight against the [Islamic State] in the east, we have the fight here in the west,” one of the 604th Infantry Battalion’s young fighters told me on the frontlines of Sirte’s Hay Dollar, near an Islamic State bomb factory, in July. It is a far cry from the demonization of the onetime Qaddafi-era general one usually hears in Misratan and Muslim Brotherhood circles. This, along with the Warfalli and Firjani tribal affiliation of some of the 604th batallion’s members, has led to whispers of them acting as Haftar’s sleeper cells.

For now, however, these differences take a backseat to combat against the Islamic State. In July, I saw fighters from the 604th battalion working closely with powerful, though less-ideological, Misratan armed groups to coordinate their battlefield movements against the group. But privately, many of these Misratan commanders wonder what’s next in Sirte after the fight against the Islamic State, and whether and how these latent tensions will escalate.

The Pressure Rises in Tripoli and Benghazi

In the capital, they already have. There, Kara’s Special Deterrence Force has proven a bulwark of support for the embattled Presidency Council. It has broken up Islamic State networks inside the capital, as well as assisting like-minded Salafi fighters in Sabratha and, more recently, Sirte in combatting the terrorist group. In his sprawling compound at Matiga International Airport, Kara runs a prison re-indoctrination and vocation program. After Quran classes in the morning, prison inmates—an assortment of alleged drug addicts, drug dealers, and Islamic State members—practice carpentry, baking, electrical repair, and computer literacy.

But Kara’s reach across the capital is limited by both neighborhood and factional rivalries (even within Matiga airport itself) and ideological differences with other Islamist groups. Nowhere is this more evident than in his clashes with the mufti, Sadiq al-Ghariani. Kara’s forces briefly arrested a senior member of Ghariani’s Dar al-Iftaa for allegedly supporting the Islamic State. Kara has also reportedly detained Tripoli-based Islamist fighters from Benghazi, backed by Ghariani, that are battling Haftar. These actions, along with Kara’s tolerant attitude toward Haftar’s dominance in the east, has enraged more rejectionist factions, in Tripoli, Misrata, and Benghazi. Kara’s response, conveyed to me in March, is that according to Salafi doctrine “one is obligated to follow the wali al-amr in whatever territory one sits.”

In the east, there are similar tensions over the Madakhlis’ loyalty and intentions.

In the run-up to Haftar’s Operation Dignity, eastern-based intelligence services removed Salafi figures from Qaddafi-era watch lists and began actively co-opting them into the fight against Benghazi’s jihadist and Islamist formations. It was not hard to do. Some had already been targeted in the spate of assassinations that rocked Benghazi from mid-2013 to early 2014. The murder in 2013 of Colonel Kamal Bazaza, a popular Salafi cleric and the head of the Islamic affairs department in the Benghazi Security Directorate provided the catalyst for many to mobilize.

Some Libyan Madkhalis joined existing Libyan National Army units allied with Haftar. For example, Ashraf al-Mayyar al-Hasi, a former field commander in the 17 February Brigade and his deputy Nafati al-Tajuri joined the Saiqa (Thunderbolt) Special Forces. Other Madkhalis joined an exclusively Salafi unit, the Tawhid Battalion commanded by Izz al-Din al-Tarhuni. Similar Salafi fighting units coalesced in Al-Marj around Haftar and in nearby Al-Bayda.

By many accounts the Salafi fighting groups, and especially the Tawhid Battalion, fought effectively together with the Libyan National Army and especially with various irregular “neighborhood protection” groups or youth “support forces” throughout Benghazi. In the Benghazi neighborhood of Majura, for example, young fighters from the Majura Protection Force interviewed last September described a symbiotic relationship with the Salafists, who were present at the founding of their neighborhood force. In combat with the Islamic State and the Benghazi Revolutionaries’ Shura Council, Majura fighters blared recorded sermons of the deceased Salafi cleric Kamal Bazaza across the frontlines. And, as in the case of Kara’s Deterrence Force, clerics allied with the Tawhid Battalion went into Libyan National Army-controlled prisons to conduct a theological re-education of imprisoned fighters from the Islamic State and Benghazi-based jihadists.

“Four days ago, I went to the prisons,” one of them told me in Benghazi last fall, “and I talked to these young men and I told them you have it all wrong about the taghut (tyrant) and the kuffar (unbelievers).

But, as in the west, a number of eastern security actors and social figures harbor doubts about the Salafists’ long-term goals. An Ubaydat tribal notable from Tobruk told me in September last year, “[W]e are with them for now against the Brotherhood, but they are extremist, they keep secrets.” A Benghazi-based Ministry of Interior official believed it was unwise for them to be concentrated in their own battalion; they needed to be broken up, given regular army identification numbers, and deployed across the frontlines.

Starting in early 2015 a number of local and external dynamics shifted the Salafi playing field. Tawhid’s Tarhuni died fighting in Benghazi’s Suq al-Hut district in February 2015. Later that month, Rabia bin Hadi al-Madkhali issued a fatwa forbidding participation in the Dawn-Dignity conflict—part of a broader shift in Saudi Arabia’s regional policy following the ascension to the throne of King Salman, which included a downgrading of the Muslim Brotherhood threat and efforts to reconcile Libya’s opposing camps. The Tawhid Battalion fragmented and its members subordinated themselves to various Libyan National Army units, including the 302 Special Forces Battalion, the Marine Special Forces, the 210 Mechanized Infantry Battalion, and others.

But this was ultimately more a rebranding than a tempering or dilution of the Salafists’ military influence. A number of these outwardly “regular” Libyan National Army military units are in fact deeply Salafi and sectarian in outlook, with sub-units maintaining the name “Tawhid Battalion” and the sermons and statements of Madkhali clearly displayed on their social media outlets.

Moreover, the Salafists have not disappeared from the battlefield. This summer, they mobilized against the Benghazi Defense Brigades, an anti-Haftar Islamist armed group backed by Sadiq al-Ghariani that advanced on Benghazi from the west. Madkhali had shifted his stance once again, publicly exhorting his Libyan followers to confront the Brigades, which he labeled a Brotherhood group.

Taken in sum, these dynamics underscore the growing power of the Salafists, specifically the Madakhlis, as well as the persistent reach of the Gulf Arab states into Libya’s security affairs. International actors are rightly focused on defeating the Islamic State and reconciling Libya’s political divides. But growing fissures within the Islamist field deserve attention, too. The rise of the so-called quietist Salafists, particularly in policing and religious institutions, has been one by-product of Libya’s worsening conflict, regional meddling, and, more recently, the fight against the Islamic State. Security actors in Tripoli, Misrata, Benghazi, and Bayda all acknowledge harnessing the power of Salafi fighting groups in their campaigns against political rivals and the Islamic State. But they are equally frank in admitting the unknown effects of this co-option on Libya’s future.

The author is grateful for the research assistance of Carnegie Junior Fellow Caroline Zullo.