What's the Difference Between Sunni and Shiites? ISIS Attacks Muslims in Kabul Explosions

The Islamic State militant group has taken responsibility for an attack on a Shiite community center in Kabul, Afghanistan, that left at least 41 dead and scores wounded. HAIDAR HAMDANI/AFP/Getty Images

The Islamic State militant group, or ISIS, claimed responsibility for a series of explosions in the Afghan capital of Kabul that left at least 41 dead and 84 wounded on Thursday, according to reports. An unknown number of suicide attackers set off an explosion outside a Shiite Muslim cultural center before going inside and detonating additional explosive devices in the basement of the building, the Interior Ministry spokesman Naib Danish said, according to the Associated Press.

The attack was the militant group's latest against the Shiite minority, which accounts for about 10 to 15 percent of the Afghan population, according to CIA data. Nearly all of Afghanistan's 34 million person population is Muslim, with the vast majority, about 85-90 percent identifying with Sunni Islam. Islamic State fighters identify with the Sunnis and consider Shiite Muslims heretics. The militant group has killed more than 100 Shiite Muslims in separate terror attacks this year, according to Esri, a mapping analytics organization that tracks terror attacks

Afghan President Ashraf Ghani called the attack a "crime against humanity." Dozens of people, many of them students, were gathered in the center's basement for a panel discussion on the anniversary of the former Soviet Union's invasion of Afghanistan in 1979 when the blasts occurred, Reuters reported.

The center also houses the news-agency Afghan Voice. A reporter with the outlet told Reuters one journalist had been killed and another wounded.

This is the latest attack on the Shiite minority population in Afghanistan ISIS has claimed responsibility for. The group attacked two mosques hours apart from each other, killing at least 88 people in October.

Kabul blast: What we know
Attack targets Shia minority at cultural centre
40 killed, dozens wounded
Women, children among dead
President: 'Crime against humanity'
Afghans rush to hospital to donate bloodhttps://t.co/trhnJpVyCP pic.twitter.com/Iz5FYfJNKs

— Al Jazeera News (@AJENews) December 28, 2017

The group also said it was behind another suicide bomber attack in Kabul that left five dead and 33 wounded in September. ISIS also claimed responsibility for another attack on a news organization in Kabul, Shamshad TV, in November. In that incident, two men wearing police uniforms and armed with automatic rifles and suicide vests walked into the station.

In all, ISIS has been behind or suspected in 15 attacks in Kabul alone this year that resulted in 298 deaths, according to Esri.

Islam fractured into two main practices, Sunni and Shiite, centuries ago after the Prophet Muhammad's death in A.D. 632. Both groups practice their faith according to the Quran and the teachings of the Prophet Muhammad, and generally agree on the fundamental principals of Islam. Where they differ tends to be over historical events and leadership.

There was disagreement over who would become the caliph, or the "deputy of God" after the prophet's death. Most sided with Abu Bakr, a close follower of the prophet, though a small minority aligned with his son-in-law and cousin Ali. The minority believed the prophet had chosen Ali to succeed him as the political and spiritual leader.

Those who followed Abu Bakr became Sunnis while Ali's followers became Shiites.

The relationships across divisions were further eroded when the prophet's wife Aisha challenged Ali's leadership. The two sides attacked each other, with Ali defeating Aisha in what became known as the Battle of Camel in A.D. 656. It was not the last time Ali's leadership would be challenged.

Ali's son Hussein would die in a subsequent battle and be lauded as a martyr in the Shiite community.

In the centuries that followed, the two communities' differences grew. Shiites have come to rely heavily on imams as spiritual guides, believing them to be divine leaders from among the prophet's family. Sunnis, however, take their lead on a range of issues, like worship, criminal law, gender and family, from four foundational religious schools.