“Iraqis need to stop killing each other,” said Sadeq al-Mousawi, who was nearby but unharmed when the suicide bomber struck. “What did the victims of today do to be killed? Sectarianism has no mercy against anyone, and there are groups of criminals and militias used by officials and politicians to achieve their specific agendas.”

Though violence in Iraq has moderated in recent months, in the wake of the American troop withdrawal, the nature of Monday’s attacks laid bare the sectarian disputes that still poison Iraqi society. Attacks on Shiite pilgrims are still common, and several days ago a series of explosions rocked Baghdad, killing at least 17, including more than a dozen in a single strike at a market in a predominantly Shiite neighborhood.

Some at the bombing scene on Monday said they believed the government was behind the attack, a sentiment expressed frequently by Iraqis who know too well that many of their elected officials have in the past been linked to militias.

At the Sunni Endowment in Adhamiya, where the roadside bomb was discovered, an employee complained that the Shiites “are trying to take everything from the Sunnis, and now they are taking our mosques, one by one.”