Five homemade bombs were hurled into a crowd gathered at a Shiite Muslim shrine in Bangladesh’s capital early morning on Saturday, sending the tens of thousands who had gathered for the annual holy ritual of Ashura running and screaming.
Of the five explosives, three detonated, collectively killing one teenage boy and wounding more than 100 people, officials said.
Police shortly arrested two suspects and discovered two unexploded bombs.
Officials are rejecting claims that the Islamic State was responsible for the attack, contrary to what the group posted on Twitter, according to the SITE Intelligence Group, an American organization that monitors jihadist activities.
IS, a Sunni militant group, allegedly said in a statement that "soldiers of the Caliphate in Bangladesh" were able to detonate explosives in a temple of "polytheists in the city of Dhaka, during the holding of their polytheist rituals."
Dhaka police said there is no evidence to corroborate those claims.
"So far we have not found any link to any militant group in the attack," police spokesman Muntashirul Islam told Agence-France Presse.
Though clashes between Sunni and Shiite Muslims are common in many countries, sources say they are rare in this part of the world. Saturday’s bombing has left what locals describe as a generally peaceful – even fraternal – Muslim community in shock.
"This is unprecedented," Feroz Hossain, curator of the building at the beginning of the planned march route, told reporters. "We have been observing this [holiday] for ages, but we never faced anything like this."
Shiites are a minority in Bangladesh, but they are generally not discriminated against, and attacks against them are virtually unheard of, reports the Associated Press.
The Ashura festival – which is the most important holiday of the year for many Shiites and, while less central to Sunnis, is still widely observed by Sunni Muslims – has proceeded peacefully for 400 years, The New York Times reports, typically "drawing throngs of Sunni Muslims who wind through the narrow streets of Old Dhaka alongside their Shia neighbors."
But this year’s tragedy comes as Bangladesh has seen a disturbing surge in the number of attacks claimed by various Islamic extremist groups, according to the AP.
Four bloggers known to be atheists were murdered this year after Islamic extremists in 2013 placed their names on a widely circulated hit list.
A senior Dhaka police official called this weekend's bombing an attempt at "sabotage."
"Given the nature of attacks, I think this has been done to create chaos in the country," said Asaduzzaman Mia. "It is clear that it was a planned attack."
For now, those participating in Ashura, a multi-day ritual, have said they are determined to continue on. At noon on Saturday, thousands were still gathered at the parade's original starting spot.
"We are not afraid," said Rashed Hossain as he stood near the crowds. "We are ready to move ahead with the procession."
This report contains material from The Associated Press.