Thirteen U.S. service members and at least 170 Afghan civilians died Thursday in a suicide bombing near the international airport in Kabul, the capital of Afghanistan. The Islamic State group’s Afghan affiliate, called the Islamic State Khorasan, or ISIS-K, claimed responsibility for the attack.

For many, the affiliate group is obscure and its identity confusing amid a conflict that has been dominated by the Taliban and its battle with U.S. forces and the Western-backed government it recently toppled. How much of a threat ISIS-K poses to U.S. interests has been the subject of controversy in recent years even among intelligence and policy experts.

The group, which formed in 2015, is the local franchise of the Islamic State of Iraq and Syria, or ISIS — the Islamic extremists who swept to power in large parts of those two countries in 2014 before it was beaten back by local and U.S. coalition forces. According to a recent government intelligence document obtained by Yahoo News, ISIS-K “has had relations with the Pakistani Taliban (Tehrik-i-Taliban Pakistan), and has a large membership of Pakistani nationals. The group has had presence in Afghanistan, Pakistan, Tajikistan, Uzbekistan and India.”

The goal of ISIS, the main organization, is to create a global Islamic state, or caliphate, that follows its own very extreme interpretation of Islam. Its methods are notoriously brutal, including filmed beheadings, mass executions, rape and sex slavery. (The group and its methods bear little resemblance to the religion that is practiced by the vast majority of the nearly 2 billion Muslims around the world.)

The former leader, or caliph, of ISIS, Abu Bakr al-Baghdadi, died in a U.S. raid in October 2019 and was replaced by Abu Ibrahim al-Hashimi al-Qurashi.

Local affiliates — or “provinces,” as ISIS calls them — pledge loyalty to the caliph. They also get strategic direction from the core ISIS leadership in Iraq and Syria, and they share its broader goals. But affiliates largely run their own day-to-day operations, according to Naureen Chowdhury Fink, executive director of the Soufan Center.

“There isn’t always a direct relationship with the core,” Fink said. “But a lot of the guidance and, say, strategic direction that ISIS’s core set up, the affiliates take and localize.”

ISIS has carried out deadly attacks in the U.S. and in Europe, some directed by the group’s leadership in Iraq and Syria and others simply inspired by its rhetoric. But experts who spoke with Yahoo News said ISIS-K is primarily focused on the fight in and around Afghanistan and Pakistan.

From its beginnings, ISIS-K has defined itself against the Taliban and al-Qaida. The split is both ideological and strategic.

Ideologically, ISIS-K is part of a worldwide movement to build a global Islamic caliphate centered in Iraq and Syria, with the leader of ISIS as its head. It has described the Taliban as “filthy nationalists” who are primarily concerned with getting and maintaining power inside Afghanistan.

The Taliban’s negotiations with the U.S. and its move into power have also given ISIS-K an opportunity to paint the Taliban — which impose their own extreme interpretation of Islamic law — as collaborators with the U.S. and other Western powers.

“It sort of helps confirm the [ISIS-K] rhetoric that it’s another flavor of Westernized haram government,” said Fink, using an Arabic term for something that is forbidden in Islam.

At its height, ISIS-K had as many as 4,000 fighters in Afghanistan, according to Andrew Mines, a research fellow at the Program on Extremism at George Washington University. It also controlled some territory within Afghanistan — one of the prerequisites for a caliphate. But Afghan and U.S. coalition forces retook those territories in November 2019. Around 1,400 ISIS-K fighters surrendered, putting the group in what Mines called “a rebuilding phase.”

The group has also suffered a series of losses in its senior leadership.

Still, its setbacks in 2019 and the Taliban’s rise to power could make ISIS-K all the more dangerous as it tries to stay relevant and attract disaffected Taliban fighters to its ranks, Mines said.

“When they are on that low rung, these kinds of strategic attacks become much more important to stay relevant, to signal resolve, and just to basically stay on the map and keep the small numbers of fighters that they have left in their ranks,” he said.

The key to the group’s survival since 2015 has been its ability to replenish its ranks after counterterrorism operations, its willingness to form strategic alliances with other militant groups in the region, and its deep bench of potential fighters from Afghanistan, Pakistan and elsewhere.

Both Mines and Fink emphasized that it’s a regional group that operates across the Durand Line that divides Afghanistan and Pakistan. That means any attempt to rein it in will require more than just Afghan, U.S. or coalition efforts.

“What we need is a reasonable strategy that coordinates with regional partners,” Mines said.

That looks increasingly unlikely as the security situation deteriorates and as Pakistan and other regional powers jockey for influence in the new Afghanistan.

Current estimates put the size of ISIS-K at between 1,500 and 2,000 fighters in the region. Even before the suicide bombing at the Kabul airport, the group carried out a string of at least 77 attacks in the first four months of 2021 alone, according to the United Nations.

Those attacks have tended to target religious and ethnic minorities within Afghanistan, which experts said is an intentional tactic to drive a wedge in society.

ISIS members and their weapons after their surrender to the Afghanistan government in Jalalabad in November 2019. (Noorullah Shirzada/AFP via Getty Images)

But ISIS-K has also targeted Afghan security and intelligence forces, according to Mines, in a way that’s similar to what ISIS did in Iraq before its rapid rise to power in 2014. That could mean that Taliban security and intelligence forces will now be in the crosshairs.

Attacks like the one at the airport in Kabul are meant to undermine public confidence in the Taliban’s ability to maintain order and destabilize the country, experts said, creating a vacuum for ISIS-K to fill. The question now is whether the Taliban can live up to their promise of bringing stability to the country — even if it is at the end of a truncheon.

“ISIS-K is a sworn enemy of the Taliban,” Madiha Afzal, a foreign policy fellow at the Brookings Institution, said after the airport attack. “Even before today’s complex attack in Kabul, there had been real questions about how effective an eventual Taliban government would be in warding off ISIS-K threats.”

Lost in all this are the Afghans who’ve spent the past two decades trying to build a civil society that neither the Taliban nor ISIS-K is likely to tolerate. The Taliban’s rise to power has already seen thousands leave the country, including journalists, activists, athletes and even its celebrated girls’ robotics team.

Fink cautioned against letting ISIS-K paint the Taliban as “the good bad guys” just because they are willing to negotiate with the United States.

“Really, they’re not so different if you’re a civilian in their midst,” she said./Yahoo News