The burial of Omar Abed Hammoudi was a furtive affair, conducted in haste in the far corner of a cemetery filled with those who died in the last round of bloodletting in Baghdad.

The circumstances of his death suggested that the killings have started again. Snatched from his home by masked and uniformed men in a mostly Shiite neighborhood, Hammoudi, who was Sunni, was found dumped outside a mosque the following day, strangled and with a bullet wound to his head — a sequence of events that chillingly recalled the slaughter of the 2005-07 civil war.

“He was killed because of his sect,” said Hammoudi’s brother, Ahmed, as he hurried out of the graveyard this month with a small group of mourners, too afraid to speak within sight of the nearby security forces, who are deemed loyal to the Shiite-led government.

In the weeks since the Islamic State of Iraq and Syria — which on Sunday said it would now be known simply as the Islamic State — captured the northern Iraqi city of Mosul, then surged south toward Baghdad, the sense of panic that gripped the capital has abated. Confidence has grown that the Shiite-dominated security forces, bolstered by thousands of Shiite volunteers, will be able to hold back the advancing Sunni militants even as they sweep through the mostly Sunni provinces of the north and west.

But among the capital’s Sunni minority, the call to arms has induced a different dread — that they will become targets of Shiite revenge. A spate of sinister killings similar to Hammoudi’s has given weight to those concerns, rooted in memories of the darkest days of the civil war.

There is no indication yet of a return to the unchecked mayhem of those years, when gunmen roamed the streets hunting down members of the opposite sect and scores of bodies piled up daily at the morgue. Although Sunnis inflicted mayhem on Shiite communities, too, they did so mostly by blowing them up. Most of the victims of the death-squad-style killings were Sunnis, in what looked like a systematic effort to drive them out of the capital.

In the past two weeks, police reports have noted daily a scattering of similar deaths: the discovery of a body with bound hands in one neighborhood, a pair of bodies in another. Such incidents had already been mounting in recent months as the tensions foreshadowing the eruption of violence began to escalate, some Sunnis say.

“We are used to these things. This is the persecution we have faced for a long time,” said Sheik Amir al-Azzawi, who leads a government-backed Sunni movement in the Sunni neighborhood of Adhamiyah and whose son was killed by Shiite militiamen in 2006.

“I burned in that fire, and I am not willing to go through that experience again,” he said, his eyes filling with tears as he recalled his slain son. “If it starts, it will be catastrophic, but so many Iraqis lost loved ones, I think they will not allow it to happen again.”

A call to arms

The huge response to the call by Shiite clergy for civilians to take up arms to fight the advancing militants has, however, unleashed Shiite militias on a scale unseen since the surge of U.S. troops in 2007 tamped down violence. Operating in full view of the security forces and sometimes alongside them, they roam the streets in pickup trucks and SUVs, guns drawn, wearing uniforms that mimic those of the security forces and can readily be bought in stores throughout the city.

Baghdad’s Shiites, more concerned about the threat posed by the fiercely anti-Shiite Islamic State, have mostly welcomed the militias as protection against the marauders to the north.

“They have made Baghdad safer,” said Abdul Karim al-Sudani, 54, who has been working overtime sewing uniforms in his shop in central Baghdad. He offers more than 20 designs, from the routine gray uniforms worn by the police to the black outfits of the elite SWAT force.

“The opposition calls them militias, but they are only responding to a fatwa from their religious leaders,” he said. “If they don’t respond, they are committing a crime, because this is a religious order.”

It also struck some as a call to polarization. “We are at the brink,” said Abu Obaid al-Adhami, 50, who fixes cars in Adhamiyah. “They told Shiite people to take up arms, and now something that used to be hidden is taking place openly.”

Adhamiyah is one of just a handful of Sunni enclaves that remain after the sectarian war, in which Shiites, retaliating against Sunni attacks, gained the upper hand, asserted their majority status and drove Sunnis out of many neighborhoods. Tens of thousands died in 2006 alone, and thousands more are still missing.

The slaughter ended with the surge of U.S. troops and the creation of the Awakening movement, which saw Sunnis team up with American troops to fight al-Qaeda in return for protection — as much from the Shiite militias as from the extremists.

‘We are victims’

But there was no reconciliation, and in the years since U.S. forces left, Sunnis have smoldered over what they perceive as unequal treatment at the hands of Prime Minister Nouri al-Maliki’s Shiite-dominated government.

In the once-mixed neighborhood of Shaab, where Sunnis are now a small minority and where Hammoudi was abducted and killed, resentment mingles with fear. Sunni families are moving out as Shiites stroll through the streets wearing their militia uniforms. Sunnis have no recourse, because they agreed to surrender their arms, said Hamid Majid, Hammoudi’s uncle, speaking several days after his funeral.

“Maliki’s army is dominated by Shiites, and Sunnis don’t have the right to hold even a pistol,” he said. “We have no weapons, while his militias circulate through our neighborhoods with their arms.”

Majid believes that his nephew was killed because his name was Omar, a uniquely Sunni name that was associated with discriminatory killings in 2005-2007. Although that cannot be confirmed, the circumstances of his abduction, as he sat outside his home with his brother and a cousin, suggest that he was singled out, according to the accounts of witnesses.

Two unmarked cars similar to those used by Iraqi police pulled up on the street, and men in uniforms similar to those worn by Iraqi security forces jumped out, the witnesses said. They pointed guns at Hammoudi, then dragged him into a car.

The next day, his body was found outside a nearby Sunni mosque. The family did not report the killing to police.

“We don’t trust the police,” Majid said. “We are victims sitting in our houses waiting to be killed.”