While uncertainty lingers in the wake of President Donald Trump’s surprise ceasefire announcement in a war that has raged between Iran and Israel—and drawn in direct U.S. intervention—another archnemesis of Tehran lurks in the shadows.
The Islamic State militant group (ISIS) operates both east and west of Iran and has also stepped up operations within the Islamic Republic itself, having claimed the deadliest operation in the nation’s post-revolutionary history in January 2024. Just earlier this month, before Israel launched its large-scale campaign of strikes, Iranian officials announced the arrest of 13 alleged ISIS members in three cities and the execution of nine other suspected ISIS members charged with plotting attacks.
Now, with Iran’s security forces having undergone their most serious challenge to date as state institutions, military sites and personnel were targeted on a daily basis by Israel, a group known for its ability to thrive in chaos and channel disaffected communities finds itself with a major opportunity.
And with Trump’s promises of peace delivered with underlying threats of further military action against Iran—even suggestions of potential “regime change”—one of his former top generals believes the possible consequences of the Islamic Republic’s collapse is something that needs to be addressed.
“We should pay attention to this in our policy discussions,” Joseph Votel, a retired four-star Army general who served as chief of U.S. Central Command (CENTCOM) from March 2016 to March 2019, told Newsweek.
Votel described militant groups such as ISIS and Al-Qaeda as being “opportunistic by nature,” noting how “they will often take advantage of voids created by a lack of governance, disenfranchisement, unemployment, lack of opportunity, and social and economic disparity to develop inroads with vulnerable populations.”
“How successfully they can do this in Iran is a matter to be watched,” he added. “The state still controls the population, but the degradation of control will provide them with operating space in the long term, either to co-opt the population or to further utilize the area as a sanctuary for their planning and operations.”
Repeating History
The history of ISIS is closely linked to U.S. military operations in the Middle East. The extremist Sunni Muslim group has its origins in Al-Qaeda in Iraq, which launched a violent insurgency against both U.S. troops and rival Shiite Muslim militias following the U.S.-led invasion of the country that toppled President Saddam Hussein in 2003.
The Islamic Republic was a fierce opponent of Saddam, having fought a devastating eight-year war with Iraq under his Baathist rule in the 1980s. His downfall offered both opportunities for Tehran to expand its influence in the fellow Shiite Muslim nation through mobilization of paramilitary groups—as well as major risks—as the subsequent destabilization gave rise to ultrafundamentalist factions, with Al-Qaeda in Iraq, later rebranded to the Islamic State in Iraq, at the helm.
Trump, in his speech Saturday announcing the U.S. strikes against three nuclear facilities in Iran, cast blame on Iran for the deaths of up to 1,000 U.S. soldiers during this time, particularly holding responsible slain Islamic Revolutionary Guard Corps (IRGC) Quds Force chief Major General Qassem Soleimani. Trump ordered the strike that killed Soleimani at Baghdad International Airport in January 2020.
Washington and Tehran’s rivalry dates back decades, but when ISIS first emerged in 2014, both contributed leading efforts to beat back the group’s lightning advances across Iraq and neighboring Syria.
The U.S. assembled an international coalition of allies and partners in a direct intervention that backed friendly forces on the ground. Iran, for its part, also deployed some military advisers, including Soleimani, but Tehran’s efforts were largely carried out by allied militias from across the region, many of whom have also been accused of inflaming sectarian tensions.
The so-called “Axis of Resistance” counts members from Lebanon, Iraq, Syria and Yemen, and as far away as Afghanistan and Pakistan. But today this coalition is in a state of disarray, having suffered severe blows in its confrontation with Israel since intervening in support of the Palestinian Hamas movement following its October 2023 attack that sparked a still-ongoing war with Israel in the Gaza Strip.
With the capabilities of these groups limited due to direct attacks from Israel as well as the weakening of their major ally in Tehran, some analysts fear yet another resurgence of sectarian tension and jihadi activity in the vein of what occurred when U.S. troops withdrew from Iraq in 2011.
“Nature abhors a vacuum,” Kamran Bokhari, senior director at the New Lines Institute for Strategy and Policy in Washington, D.C., told Newsweek. “If the Iranian state weakens and its ability to maintain domestic security weakens, this opens up opportunities for ISIS.”
He argued that “it’s kind of ironic that right now the United States is fighting the other end of the geo-sectarian spectrum,” with Trump having fought and declared victory over ISIS in 2019, only to now be challenging Iran.
Bokhari observed this trend as part of “a causality that the United States cannot sort of extricate itself from: You weaken the Shiites and Iran, and that empowers ISIS and the likes, and vice versa.”
Already, ISIS appears to be seizing opportunities across the lands of its former self-styled “caliphate.” In the most high-profile attack claimed by the group in Syria since the overthrow of Syrian President Bashar al-Assad in December by a coalition led by rival Islamist rebels and earlier weakening of fellow Axis of Resistance faction Hezbollah in Lebanon by Israeli strikes, ISIS conducted a deadly suicide bombing against a church in Damascus on Sunday.
Syria’s new government, led by a former affiliate of ISIS and Al-Qaeda who has renounced jihadi ties in recent years, has vowed to continue efforts to battle ISIS. And while interim President Ahmad al-Sharaa has thus far largely succeeded in preventing the outbreak of another full-scale civil war, blood continues spilling across sectarian lines in Syria, with security forces accused of targeting Alawites, Druze and Kurds, among other minorities.
Meanwhile, Iraq’s stability may even be more seriously threatened by the collapse of Iran’s network of militia allies.
“Iraq is not really a state,” Bokhari said. “It’s sort of held together very precariously, but it’s really a collection of non-state actors: too many Kurdish groups, too many Sunni groups and too many Shiite groups.”
“And if this doesn’t remain sort of the vassal state of the Iranians, then we can see how ISIS could emerge from both sides,” Bokhari said. “And Iran is vulnerable to ISIS from both ends.”
Testing the Ties That Bind
While Iran’s war on ISIS over the past decade has largely focused on threats emanating from Iraq and Syria, the group’s decline in these two countries has been accompanied by a steady resurgence in Afghanistan, which borders Iran to the east.
Here, the group’s self-proclaimed “Khorasan Province,” referred to as ISIS-K or ISKP, managed to establish a small, yet extremely active foothold amid the long war between the U.S.-backed Afghan government and the Taliban. As the U.S. prepared to withdraw in 2021, Pentagon officials even floated limited cooperation with the Taliban, an original enemy of the 20-year “War on Terror,” to battle ISKP.
As with the new Syrian government, Afghanistan’s Taliban administration has pledged to uproot ISIS presence in the country. Yet the group has managed to hold on to a cross-border presence, staging attacks in Iran, Pakistan and much further beyond.
Just two months after ISKP killed more than 100 people in the historic attack at a memorial procession for Soleimani in Iran in January 2024, the group struck at the heart of another enemy thousands of miles farther away, killing some 145 at a concert being held in a city hall outside of Moscow.
The suspects were identified as nationals of Tajikistan, a Central Asian state where ISIS appears to have engaged in a concerted recruitment effort stemming back at least a decade. At least hundreds of people across the Central Asian region bordering China, Iran and Russia are estimated to have joined ISIS in recent years, sparking a potential security crisis for all three powers.
In Iran, the problem is compounded by an existing presence of ethnic separatist movements among sizable non-Persian communities, including Arabs, Azeris, Baloch and Kurds. Baloch and Kurdish groups have been particularly active, and Iranian officials have tied forces among them to ISIS.
“There will be no shortage of separatists looking to take advantage of the weakness of the Iranian regime,” Colin Clarke, senior research fellow at The Soufan Center who has briefed lawmakers and military schools on counterterrorism issues, told Newsweek, “so it’s possible that ISKP could cooperate with these groups to conduct joint operations, or simply exchange weapons, know-how, or other tactics, techniques, and procedures (TTPs).”
“ISKP may smell blood in the water and seek to make the situation worse by working in tandem with anti-regime elements to attack IRGC, Basij, or other elements of the Iranian security forces,” he added.
Clarke argued that such operations would also “be appealing to ISKP because of its hardcore sectarian agenda, which helps it recruit.”
Andrew Borene, a former intelligence officer at the U.S. Office of the Director of National Intelligence now serving as executive director for global security at private threat intelligence firm Flashpoint, also saw the potential for ISIS and its affiliates to thrive in the wake of a debilitated Iranian security apparatus.
“If the Iranian state is significantly weakened by the current war with Israel, it’s possible that Iranian internal security and domestic intelligence resources would be repurposed to address external threats,” Borene told Newsweek.
“Such a situation might present an opportunistic moment for ISIS-K to escalate a terror campaign against a Shiite regime they view as an enemy,” he said. “This scenario could exacerbate existing ethnic and sectarian tensions, emboldening local armed groups and fostering further divisions.”
Yet even with ISKP’s focus on exploiting fissures within destabilized states, Iran presents a unique landscape. As analysts have previously told Newsweek, even those critical of the Islamic Republic often rally behind the central government in the face of external threats and secessionist movements.
Noting how the majority of the groups opposed to the Iranian government “are somewhat secular in nature, and quite distinct from ISIS’ Sunni Salafist ideology, even as they may represent aggrieved minority communities,” Borene said that the “missing ingredient” for the jihadis “would remain a common cause with homegrown Iranian dissidents.”
Plotting on the Sidelines
While ISIS’ enemies are many and its alliances scarce, the militants and their supporters have expressed a particular contempt for Iran. The Islamic Republic hosts the world’s largest population of Shiite Muslims, a sect of Islam they consider rafidis—a derogatory term used to describe the Shiite rejection of the first three Sunni-recognized caliphs’ authority in favor of the Prophet Mohammed’s cousin, Ali ibn Ali Talib.
Rather than taking sides in the latest conflict that has shaken the Middle East to its core, the group has remained largely neutral in what it referred to as a fight between “the State of Persia and the State of the Jews” in the latest edition of its Al-Naba magazine published Thursday.
“Throughout history, the outbreak of wars among the ranks of falsehood served the interests of truth,” the Al-Naba article read. “Muslims were aware of this and rejoiced and were encouraged by it.”
The article went on to celebrate Israel’s killing of Iranian military leaders and asserted that, “Even if Iran killed thousands of Jews, that would not make it a friend or ally of Muslims, because it is an infidel rafidi state that wages war on us, taints our blood and is hostile to the companions of our Prophet, may God bless him and grant him peace.”
Such language seeking to capitalize on global conflict and unrest mirrors the group’s messaging upon the outbreak of the Russia-Ukraine war.
“ISKP published a great deal of commentary on Russia’s war in Ukraine before its attack on Moscow and similar trends are playing out with the Israel-Iran conflict,” Lucas Webber, senior threat intelligence analyst at Tech Against Terrorism, told Newsweek. “The group’s propaganda has heavily focused on regional conflict following the October 7, 2023, attacks.”
This pattern has also been established by ISIS’ efforts to tap into grievances over the Kashmir dispute between India and Pakistan, lingering rebellion in Russia’s restive Caucasus republics and Uyghur separatism in China’s northwestern Xinjiang province.
Thus far, Webber argued, ISKP has proven “adept at analyzing and exploiting geopolitical tensions to further its objectives,” repeatedly “strategically inserting itself in regional conflicts and playing off the friction between larger geopolitical powers to expand its influence and operational reach.”
“By doing so, ISKP attempts to position itself as a significant actor within the broader Islamic State framework, despite facing substantial military and political pressure,” he added.
The developments come as ISKP increasingly sets its sight on the West, sending security agencies scrambling to intercept threats, especially at major events.
In order to fuel this war machine, however, the group continues to rely on carving out strongholds in nations already beset by strife, such as Iran.
“ISKP works to find and exploit security gaps in countries that are already engaged in conflicts,” Webber said. “These security deficiencies often arise when states are stretched thin, dealing with multiple insurgencies or geopolitical tensions, leading to weakened oversight and response capabilities.”
“ISKP identifies and takes advantage of these vulnerabilities to conduct operations, recruit members, and enhance its presence,” he added. “ISKP looks to increase instability and chaos, making it more challenging for affected states to combat extremist activities effectively.”
Christopher Costa, a professor at Georgetown University’s Center for Security Studies who previously served as special assistant to the president and senior director for counterterrorism on the White House National Security Council, warned an ISIS resurgence in the broader region, from Afghanistan to Syria, was likely to manifest in the wake of Iran’s setbacks—and the U.S. would remain a prime target.
“ISKP is perhaps the most lethal of ISIS affiliates, and dangerously opportunistic as well,” Costa told Newsweek. “I am concerned about ISIS seeking to destabilize Syria, as we saw last weekend in an Orthodox church attack in Damascus, and I believe ISKP will seek to direct attacks against Iranian interests.”
“In both cases, it’s about seeking vengeance and jockeying for media attention,” he said. “Of course, ISKP dreams of attacking U.S. interests when able to do so.”