KABUL, Afghanistan >> An Islamic State suicide bomber struck a Shiite cultural center in Kabul today, killing at least 41 people and underscoring the extremist group’s growing reach in Afghanistan even as its self-styled caliphate in Iraq and Syria has been dismantled.

The attack may have targeted the pro-Iran Afghan Voice news agency housed in the two-story building. The Sunni extremists of IS view Shiite Muslims as apostates and have repeatedly attacked Afghanistan’s Shiite minority and targets linked to neighboring Iran.

The attack wounded more than 80 people, many of whom suffered severe burns.

Local Shiite leader Abdul Hussain Ramazandada said the bomber slipped into an academic seminar at the center and blew himself up among the participants. More bombs went off just outside the center as people fled.

The IS-linked Aamaq news agency said four bombs were used in the assault, one strapped to the suicide attacker. It said the center was funded by Iran and used to propagate Shiite beliefs.

Ali Reza Ahmadi, a journalist with Afghan Voice, said he leaped from the window of his second-floor office after the first bomb went off and saw flames pouring from the basement.

“I jumped from the roof toward the basement, yelling at people to get water to put out the fire,” he said.

At nearby Istiqlal Hospital, Director Mohammed Sabir Nasib said the emergency room was overwhelmed. Additional doctors and nurses were called in to help. At the height of the crisis, more than 50 medics were working to save the wounded.

By late afternoon, Health Ministry spokesman Wahid Mujro said 41 people were dead and 84 others wounded.

The cultural center was housed in a simple building surrounded by mud-brick homes in the Shiite-dominated neighborhood of Dasht-e-Barchi, home to some of Kabul’s poorest residents.

A senior member of the local Shiite clerical council, Mohammad Asif Mesbah, said the center may have been targeted because it houses Afghan Voice. The news agency’s owner, Sayed Eissa Hussaini Mazari, is a strong proponent of Iran, and the agency’s output is dominated by Iranian news.

The center today was marking the anniversary of the 1979 Soviet invasion with a seminar about the event’s impact on the country. Mesbah said the invasion, which led to decades of war and unrest that continue to the present day, was the “beginning of all of Afghanistan’s disasters.”

Iran, a Shiite-majority country bordering Iraq and Afghanistan, has provided heavy military and financial aid to the Syrian government as well as regional Shiite militias battling IS in recent years.

The extremist group is now largely confined to a few remote patches of territory in Syria, but it retains the ability to inspire and carry out attacks further afield. Powerful affiliates in Afghanistan and Egypt’s Sinai Peninsula continue to launch regular assaults against security forces and civilians.

The IS affiliate in Afghanistan, which emerged in 2014 at around the same time the group declared a caliphate in large parts of Syria and Iraq, has vowed to target Shiites. The militants attacked the Iraqi Embassy and two Shiite mosques in Kabul earlier this year, killing dozens of people. A suicide attack on the largest Shiite mosque in the western Herat province last summer killed at least 90 people.

Afghanistan’s IS affiliate largely consists of displaced Uzbek militants and disgruntled former members of the much larger and more entrenched Taliban movement. The Taliban and IS share the goal of overthrowing Afghanistan’s Western-backed government and imposing a harsh version of Islamic law, but they are fiercely divided over leadership, tactics and ideology, and have clashed on a number of occasions. The Taliban denied any involvement in today’s attack.

Afghan President Ashraf Ghani called the attack a “crime against humanity.” The U.S. ambassador to Afghanistan, John R. Bass, said, “We remain confident the Afghan government and people, supported by their friends and partners, will defeat those behind these terrible acts.”

Pakistan, which Afghan and U.S. officials have long accused of harboring militants, condemned the “dastardly” attack in Kabul and vowed to stand with Afghanistan in its fight against terrorism. Pakistan has denied that it shelters militants and has in turn accused Afghanistan of failing to crack down on extremist groups.

Toby Lanzer, the acting head of the United Nations mission to Afghanistan, said the bombing was “another truly despicable crime in a year already marked by unspeakable atrocities.”

Afghan forces have struggled to combat both the Taliban and IS since U.S. and international forces officially concluded their combat mission at the end of 2014 and shifted to a support and counterterrorism role more than a decade after the American-led invasion that toppled the Taliban.

President Donald Trump has ordered an additional 3,800 U.S. troops to Afghanistan since announcing a new strategy in August aimed at ending America’s longest war, bringing the total U.S. forces there to at least 15,000.