The suburban Moscow concert hall assault last Friday that killed more than 130 people was the deadliest attack inside Russia in 20 years. It raised major questions about the capabilities and ambitions of the terror group that U.S. officials believe was responsible: ISIS-Khorasan, or ISIS-K, an affiliate of the self-declared Islamic State that emerged in Afghanistan.

In multiple documentaries and related reporting over the years, FRONTLINE has examined ISIS-K’s relationship with ISIS based in Iraq and Syria, its rivalry with the Taliban, its attacks inside Afghanistan — including the deadly bombings at and near Kabul’s airport during the chaotic 2021 U.S. withdrawal — and the potential threat ISIS-K posed beyond Afghanistan’s borders following the U.S.’s exit from the country.

Referring to a series of bombings inside Taliban-controlled Afghanistan in 2021, former U.S. naval intelligence officer M. Lyla Kohistany told FRONTLINE at the time, “This is ISIS-K showing through force that, in fact, it’s virtually impossible for a group like the Taliban — without the kinds of assets that the United States and the international community have — to keep them from using Afghanistan in the future as a safe haven, a sanctuary to conduct transnational terrorist attacks.”

Four men accused of carrying out the March 22 concert hall attack faced terror charges in a Moscow courtroom on Sunday. All four were identified by the Russian government as being from the Central Asian country of Tajikistan, a former Soviet republic. But it is not yet publicly known where the assault was planned. Terrorism experts have said that ISIS-K has focused on Russia for several years, fueled in part by historic grievances and Russian President Vladimir Putin’s military support of the fight against ISIS in Syria. According to a recent U.N. report, ISIS-K has been recruiting from countries across Central Asia, targeting “disillusioned” fighters from other groups.

ISIS claimed responsibility for the Moscow attack. Earlier in March, the U.S. told American citizens to avoid concert venues in the Russian capital and U.S. officials said they warned Russian officials about threats by extremists targeting large gatherings.

Putin described the March 22 attack as “barbaric” and vowed to “identify and punish” those responsible.

Explore the below documentaries, all featuring the reporting of Afghan journalist Najibullah Quraishi, for the backstory on how ISIS-K established a foothold in Afghanistan and emerged as a threat.

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Taliban Takeover

This October 2021 documentary examined the Taliban takeover of Afghanistan and the threat of ISIS-K — including how the group’s deadly Kabul airport bombing heightened concerns about the country once again becoming a staging ground for terrorists.

Taliban Country

In January 2020, FRONTLINE went on a dangerous journey inside both Taliban- and ISIS-held territory in Afghanistan and exposed the harsh reality that not only was the Taliban once again wielding power, but the threat from ISIS loomed large.

ISIS in Afghanistan

This November 2015 report chronicled the degree to which ISIS was gaining a foothold in Afghanistan, and how the group was focusing its efforts on training a new generation of fighters.

Explore FRONTLINE’s broader reporting on ISIS and the fight against the terror group in The Secret History of ISIS, The Rise of ISIS, Confronting ISIS and many other documentaries.

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