Residents of the Sunni neighborhood of Yarmouk read the Koran before Friday prayers at the Omar Muktar Musr mosque in Baghdad on Friday, July 11, 2014. (Max Becherer/Max Becherer/Polaris Images For The Washington Post)

— The Sunni worshipers who visit the main mosque in this relatively affluent neighborhood of west Baghdad are a far cry from Islamist extremists.

“We are intellectuals,” the mosque’s imam, Aday Moussa, said of a group that includes doctors, professors — and, especially, former members of Saddam Hussein’s army and security services.

The worshipers and other Sunnis interviewed in Baghdad said they have little affinity for the al-Qaeda-inspired Islamic State that routed Iraqi forces last month and declared a “caliphate” across a vast swath of the country.

But as the militants take aim at Iraq’s Shiite-dominated government, these educated, professional Sunnis leave no doubt that their sympathies lie with the insurgents.

“It’s a revolution against oppression,” Moussa said. “We believe there will be a zero hour here in Baghdad soon. The Sunnis have nothing to lose.”

Iraqi Sunnis span a wide spectrum, including rural tribal sheiks, violent jihadists, urban intellectuals and whiskey-swilling adherents to the old ruling Baath party. They are deeply divided — a fact that Nouri al-Maliki and his fellow Shiite leaders hope to exploit at a moment of national crisis.

But the militants’ sweep to power in Sunni-dominated provinces has been fueled to a significant degree by support from these other Sunnis. It has been an unlikely alliance, born of a sense of disenchantment voiced in Baghdad by men such as Moussa and his neighbors — in terms that cast a long shadow over Iraq’s future.

In a divided capital where flags of the Shiite faith flutter above army checkpoints, members of both sects murmur about that zero hour — an imagined moment when Sunni militants from the north and west wreak havoc on Shiites and bring Baghdad under their control.

“We sympathize a lot with the revolutionaries,” said a 33-year-old government bureaucrat in the Sunni-majority neighborhood of Amiriyah in west Baghdad. “And at the same time, we’re afraid of the response by the government.”

The bureaucrat was among a dozen Sunni residents of Baghdad, including former military men, who spoke with surprising fervor in interviews over the past week about the fact that they prefer the Islamists to the Shiite-led government that has marginalized them.

Maliki and his allies are widely seen here as having systematically discriminated against Sunnis, targeting them for arrests, torture, recrimination and violence over the decade since a Shiite-led government rose to power after the U.S.-led invasion of Iraq.

The Iraqi bureaucrat gave only his nickname, Abu Maryam, which means “Father of Maryam,” because he fears arrest by the Shiite militias and Shiite-dominated security forces who, he and his wife said, prowl the neighborhood at night, snatching young men and searching homes for weapons.

How the Islamic State is carving out a new country

Bodies have begun to turn up daily in Baghdad’s streets, in scenes reminiscent of the sectarian killings that ravaged the country in 2006 and 2007. Recently, militiamen seized two young men from a nearby mosque shortly before dawn, Abu Maryam’s wife said. No one knows what happened to them.

In recent days, the victims have included a middle-aged man, shot in the head in the Shiite neighborhood of Shabab; a younger man, shot in the head in the Sunni neighborhood of Ghazaliyah; and a woman and her son, fatally shot in their home in the predominantly Shiite New Baghdad area.

Some Sunnis interviewed made clear that they despise the Islamic State militants but that their feelings about the group’s territorial gains are more complicated.

“They are not Muslims,’’ said a Sunni heart surgeon in Yarmouk who spoke on the condition of anonymity because he said he feared reprisals. “Their solution — to cut and to kill people — that’s not Islam.”

But the surgeon said that he agrees with the militants that Maliki’s government should be defeated — although he said he would prefer that it be at the hands of the Sunni tribesmen fighting alongside the extremists.

Like other middle-class Sunnis and former military men interviewed, the surgeon said he has been underemployed and increasingly angry since U.S. forces invaded in 2003 to overthrow Saddam Hussein and his Sunni-dominated regime.

Fighting the extremists

In its effort to placate growing anger on all sides, Iraq’s parliament is expected to convene Sunday. It is under pressure to form a new government, possibly led by someone other than Maliki, in the hope that political change could help turn back the militants’ advance.

Some signs of intra-Sunni friction have emerged in areas controlled by the Islamic State, including sporadic fighting between militants and the more-secular former Baathists in Salahuddin province in central Iraq.

The United Nations has said that 13 Sunni clerics were executed last month in the northern city of Mosul for refusing to pledge allegiance to the militants. Osama al-Nujaifi, a Sunni who until recently was speaker of parliament, said further splits in Mosul have been ignited by the militants’ kidnapping of some former Iraqi military commanders in Mosul.

But Nujaifi and others say Iraq’s sectarian divisions run so deeply that it will take more than a new government to turn the tide.

Nabeal Younis, a political science professor at Baghdad University, said the Shiite-dominated government and its security forces must be restructured to allow more Sunnis — even those disillusioned with Maliki — to join Baghdad and fight the insurgents.

“When the people feel that the government is a national, patriotic one, working for all Iraqis rather than a few people, they’ll fight,” he said.

Seven years ago, U.S. forces in Iraq backed what was known as the Awakening movement by working with Sunni tribal leaders to fight the insurgent group al-Qaeda in Iraq, the precursor to the Islamic State. After the U.S. military handed over administration of the program to the Iraqi government, the Awakening fell into disarray, a collapse that critics blame on Maliki’s government.

“They didn’t pay their salaries or arm them. On the contrary, they were arresting them, and charged them with being terrorists,” Nujaifi said. He and other Sunnis suggested that Iraq might have averted the current crisis if Maliki had chosen a different course.

Meanwhile, Baghdad is bracing for more bloodshed.

“If the different parties don’t work together as soon as possible, I think it’s going to be very dangerous,” Younis said. He likened the capital to a dormant volcano. “If there is an explosion, it will be hard to stop.”

Khalid Ali in Baghdad contributed to this report.