More than 133 people were killed and more than 100 others were injured a bold attack at concertgoers at Moscow’s Crocus City Hall before a performance by a Soviet-era rock band on Friday.

Attackers in camouflage uniforms opened fire and reportedly threw explosives into the concert hall, which was engulfed in flames and its roof collapsed following the deadly attack.

Eleven people were arrested, including four people directly involved in the armed attack, the Russian news agency Interfax reported on Saturday.

According to Reuters news agency, the Afghan affiliate of ISIS – also known as the Islamic State in Khorasan Province, ISKP (ISIS-K) – has claimed responsibility for the attack and US officials have confirmed the authenticity of that claim.

Here’s what we know about the group and their possible motive for the Moscow attack.

Afghanistan branch of ISIL

The group remains one of ISIL’s most active affiliates and takes its title from an ancient caliphate in the region that once covered areas in Afghanistan, Iran, Pakistan and Turkmenistan.

The group emerged from eastern Afghanistan in late 2014 and consisted of renegade fighters from the Pakistani Taliban and local fighters who had pledged allegiance to the late ISIL leader. Abu Bakr al-Baghdadi.

Since then, the group has gained a fearsome reputation for its brutality.

Murat Aslan, a military analyst and former colonel in the Turkish army, said ISIL’s Afghanistan branch was known for its “radical and harsh methods.”

“I think their ideology inspires them when choosing their goals. First, Russia is in Syria fighting Daesh [ISIL] like the United States. This means they view such countries as hostile,” Aslan told Al Jazeera.

“You are in Moscow now. Before, they were in Iran, and we will see many more attacks, perhaps in other capitals,” he added.

Although their membership in Afghanistan is said to have declined since a peak in 2018, their fighters still pose one of the biggest threats to the Taliban’s authority in Afghanistan.

Previous attacks by the group

ISKP fighters took responsibility for 2021 attacks At least 175 civilians died outside Kabul airport, 13 US soldiers were killed and many dozens were injured.

The ISIL offshoot was previously blamed for carrying it out a bloody attack on a maternity ward in Kabul In May 2020, 24 people died, including women and small children. In November of the same year, the group carried out an attack on Kabul University, killing at least 22 teachers and students.

In September 2022, the group claimed responsibility for a deadly suicide attack on the Russian Embassy in Kabul.

Last year, Iran blamed the group for two separate attacks on a major shrine in southern Shiraz – the Shah Cheragh – in which at least 14 people were killed and more than 40 injured.

The US claimed it intercepted communications confirming the group was preparing attacks before coordinated suicide bombings in Iran killed nearly 100 people in the southeastern Iranian city of Kerman in January this year. ISKP claimed responsibility for the attacks in Kerman.

Why is ISIL attacking Russia?

Defense and security analysts say the group has targeted its propaganda in recent years against Russian President Vladimir Putin for what he says is Russia’s repression of Muslims.

“Russian foreign policy was a big warning sign for ISIS [ISIL]“,” Michael Kugelman, director of the South Asia Institute at the Wilson Center in Washington, told Al Jazeera. “The Soviet invasion of Afghanistan, Russian actions in Chechnya, Moscow’s close ties with the Syrian and Iranian governments, and especially the military campaigns that Russia has waged against ISIS fighters in Syria and – through Wagner Group mercenaries – in parts of Africa.”

All of this has led to Moscow becoming the focal point of the ISKP’s “extensive propaganda war,” said Amira Jadoon, an assistant professor at Clemson University in South Carolina and co-author of “The Islamic State in Afghanistan and Pakistan: Strategic Alliances and Rivalries.”

“Russia’s commitment to the global fight against ISIS and its allies, particularly through its military operations in Syria and its efforts to establish ties with the Afghan Taliban – ISIS-K’s rival – makes Russia a key adversary of ISIS/ISIS-K.” Jadoon told Al Jazeera.

If the Moscow attack is “definitely attributed to ISKP,” Jadoon said, the group hopes to gain support and advance “its goal of becoming a terrorist organization with global influence” by showing that it is carrying out attacks on Russian territory could start.

“ISK [ISKP] has consistently demonstrated its ambition to develop into a formidable regional entity… By directing its aggression towards countries such as Iran and Russia, ISK not only confronts regional heavyweights but also underscores its political relevance and operational reach on the global stage Jadoon said.

Kabir Taneja, a fellow at the Strategic Studies Program at the Observer Research Foundation – a think tank based in New Delhi, India – told Al Jazeera that Russia is viewed by ISIL and its affiliates as “a crusading force against Muslims.”

“Russia has been a target for ISIS and not just ISKP since the beginning,” said Taneja, author of the book “The ISIS Peril.”

“ISKP attacked [the] “Russian Embassy in Kabul in 2022, and over the months, Russian security agencies have increased their efforts to target pro-ISIS ecosystems both in Russia and on its borders, particularly in Central Asia and the Caucus,” he said.

In early March, Russia’s Federal Security Service, better known as the FSB, said it had foiled an ISIL plan to attack a Moscow synagogue.

“The most compelling current motivation for ISIS-K to attack Russia is the Taliban factor. “The Taliban is a bitter rival of ISIS, and ISIS considers Russia a friend of the Taliban,” Kugelman said.

Moscow’s close ties with Israel are also anathema to IS ideology, Taneja said.

“So these tensions are not ideologically new, but they are tactical,” he told Al Jazeera.

There’s another factor: The armed group has coalesced into a formidable force largely out of the world’s attention after setbacks in Syria and Iran.

“ISKP in Afghanistan has increased significantly in strength… and this applies not only to ISKP, but also to ISIS in its original areas of operation, Syria and Iraq [an] Increase in operational capabilities,” said Taneja. Today, he added, it is “ideologically powerful, although politically, tactically or strategically…not so powerful.”

That’s a challenge for a distracted world, he said.

“How to address this is the big question at a time when great power competition and global geopolitical unrest have pushed counter-terrorism into the background,” Taneja added.

How did ISIL respond?

ISKP’s social media channels were “jubilant” after the attack on Moscow, said Abdul Basit, senior associate fellow at the S Rajaratnam School of International Studies in Singapore.

“They are celebrating the attack,” Basit told Al Jazeera, adding that supporters were “translating and disseminating the claim of responsibility” from the ISIL-affiliated Amaq news agency.

Basit said that ISIL’s method of operation is to reinforce a Propaganda campaign in advance of large-scale attacks, and this has been seen in recent anti-Russian messages. Such attacks “increase the credibility” of armed groups, Basit explained, which in turn “increases the scope of their funding, recruitment and propaganda.”

Given the key role played by ISIL recruits of Central Asian origin – particularly Tajiks – as the group held territory in Syria, further attacks in Russia and elsewhere are possible, he added. They have now returned to the Central Asia region and their intention to carry out attacks has now been realized in the capability, Basit said.

Previous attacks in Russia

Moscow and other Russian cities have been targets of previous attacks.

In 2002, Chechen fighters took more than 900 people hostage in a Moscow theater, the Dubrovka, demanding the withdrawal of Russian troops from Chechnya and an end to Russia’s war in the region.

To end the standoff, Russian special forces attacked the scene, killing 130 people. Most were suffocated by a gas that security forces used to render the Chechen fighters unconscious.

The deadliest attack in Russia was the 2004 Beslan school wins which was carried out by members of a Chechen armed group that sought Chechnya’s independence from Russia. The siege killed 334 people, including 186 children.