Men carry the coffin of a victim on Sunday, one day after a suicide attack killed more than 80 in Kabul. (Mohammad Ismail/Reuters)

Afghan President Ashraf Ghani on Sunday ordered a 10-day ban on public protests after a suicide bombing claimed by the Islamic State killed more than 80 people and wounded hundreds at a peaceful demonstration here Saturday. The protesters, mostly members of the Shiite ethnic Hazara minority, were demanding better access to electrical power in several rural provinces.

But the devastating terrorist attack, the deadliest in Kabul since the overthrow of Taliban extremist rule in 2001, raised fears that sectarian violence could be unleashed in the Sunni-majority Muslim country, deliberately fanned by the eruption of mass carnage in the Afghan capital at the hands of the Islamic State, the Middle Eastern-based Sunni group known here as Daesh.

“If Daesh has indeed conducted this attack as they claim, then their first goal is clear: to kill the Shiites here as they have been killing them in Iraq,” said Ahmad Zia Rafat, a professor at Kabul University. “Their second goal is to create panic, destabilize society and put pressure on the government.”

The two-year-old Ghani government has been struggling to meet public demands for reform and improved living standards while trying to beat back an aggressive Taliban insurgency, which has launched repeated attacks in Kabul and other parts of the country this year. Until Saturday, the Islamic State’s recruitment and armed operations had been confined to a far eastern region near Pakistan’s border.

Earlier this month, President Obama announced he was slowing the planned withdrawal of U.S. troops from Afghanistan, leaving about 8,400 in the country through the end of 2017. His move was supported by numerous military officials and experts, who said Afghan forces were not yet prepared to defeat the Taliban on their own and that the United States needed to reinforce its message of long-term commitment to the country. Most U.S. troops are involved in training or counterinsurgency. 

Now, with both the Islamic State and the long-oppressed Hazara minority flexing their muscles, the Ghani government must deal with a new source of potential upheaval and seek to ensure that Afghanistan’s Western-backed war does not veer into sectarian conflict. 

Even as Ghani declared Sunday a day of national mourning and Hazara community members buried dozens of victims in a hastily dug mass grave southwest of the capital, some Hazara leaders blamed the president for failing to protect their gathering and said they would press on with their demands despite the ban on protests. 

“More than 100 young people died for the cause. If the government doesn’t reroute the power line, we will continue our protests even if it costs our lives,” said Raihana Azad, a Hazara member of parliament and leader of the power movement. “If we don’t continue to protest, it will be an insult to the blood of those who were killed yesterday.”

In recent years, Afghanistan has largely avoided a reprise of the sectarian clashes that destroyed Kabul during the civil war of the early 1990s and that in recent years have brought bloodshed and chaos to Pakistan, Iraq and Syria. The only previous major attack against Afghan Shiites was the bombing of a Kabul mosque in 2011 during a religious holiday. That attack, which left 70 dead, was claimed by Pakistani Sunni militants.

But the once-docile and impoverished Hazara minority, long abused and ostracized by ethnic Pashtun Sunni leaders, has been gaining strength and voice under civilian rule, holding ever-more elaborate religious holidays, demonstrating against discrimination and insisting that the government route power lines through their rural heartland. Shiites make up about 10 percent of the Afghan population, with power bases in Kabul and the north-central province of Bamian.

Since taking office, Ghani has tried to appease the Hazaras by allowing them to hold peaceful demonstrations and offering to negotiate over the placement of power lines. Senior Hazara leaders have opposed the recent protests, which have been led by dissident leaders, students and community activists, and the government has placed cargo containers on major roads to contain their marches.

In addition, there are outside forces that could exacerbate sectarian conflict here. Iran, which took in huge numbers of Shiite refugees from Afghan wars, has sought increasing influence in postwar Afghan society. In Syria, some Hazaras have fought on the side of government troops against Sunni militias, including the Islamic State. 

“The goal of Daesh is to fan sectarian war in Afghanistan, but they will not succeed because the people are smart and have learned a lot from years of long wars,” said Mohammad Nateqi, a former Afghan diplomat and analyst.

But several Hazara political and intellectual figures said they were concerned that the Ghani government would not be able to protect them, and some suggested that Saturday’s attack was abetted by collaborators inside the government.

Mohammed Alizada, a Hazara member of parliament, said the Islamic State has two factions of loyalists operating in Afghanistan, one made up of moderate former Taliban members and one more foreign-dominated and extreme. If the second group grows stronger, he said, “I don’t think the Afghan government will be able to defend Shiites against them without the help of the international community.”

Constable reported from Fairfax, Va. Sayed Salahuddin contributed from Kabul.