An eruption of violence in Iraq is threatening to undo much of what U.S. troops appeared to have accomplished before they withdrew, putting the country’s stability on the line and raising the specter of a new civil war in a region already buckling under the strain of the conflict in Syria.

In the western Iraqi province of Anbar, Sunnis are in open revolt against the Shiite-dominated government of Prime Minister Nouri al-Maliki. Militants affiliated with al-Qaeda have taken advantage of the turmoil to raise their flag over areas from which they had been driven out by American troops, including the powerfully symbolic city of Fallujah, where U.S. forces fought their bloodiest battle since the Vietnam War.

The Iraqi army, trained and equipped at great expense by the U.S. military before it pulled out of the country in 2011, is struggling to hold its own against what is at once a populist revolt and a militant insurgency.

On Monday, Maliki urged the people of Fallujah to expel al-Qaeda-­affiliated militants to avert a full-on attack, echoing calls made by U.S. forces a decade ago when they warned residents to leave the city or suffer the consequences.

“The prime minister appeals to the tribes and people of Fallujah to expel the terrorists from the city in order to spare themselves the risk of armed clashes,” Maliki said in a statement read on state television as convoys of military personnel, tanks and heavy equipment headed toward the city to reinforce troops who were surrounding it.

1 of 14 Full Screen Autoplay Close Skip Ad × The intertwined conflicts in Syria and Iraq View Photos An eruption of violence in Iraq is raising the specter of a new civil war in a region already buckling under the strain of the conflict in Syria. Caption An eruption of violence in Iraq is raising the specter of a new civil war in a region already buckling under the strain of the conflict in Syria. Jan. 5, 2014 Armed Sunni fighters take up positions in the western Iraqi city of Fallujah. Three groups are engaged in fighting in Anbar province, which includes Fallujah: local tribes, Iraqi security forces and militants from the al-Qaeda-linked Islamic State of Iraq and Syria. Mohammed Jalil/EPA Buy Photo Wait 1 second to continue.

Instead, most residents were trying to leave, packing their possessions into cars and fleeing in any direction they could, just as they did ahead of the U.S. assault on the city in November 2004.

The Obama administration has responded to the crisis by promising to accelerate weapons deliveries to the Iraqi government, including Hellfire missiles and surveillance drones. White House spokesman Jay Carney said U.S. officials are working with the Iraqi government “to develop a holistic strategy to isolate the al-Qaeda-

affiliated groups.”

But most analysts and Iraqis say the problem is rooted, above all, in the Maliki administration’s failure to reach out to Sunnis and include them in the decision-making processes of the coalition government, thereby enhancing a sense of Sunni alienation from the authorities in Baghdad that began when U.S. troops invaded Iraq and toppled Saddam Hussein, a Sunni, in 2003.

“Extra weapons and drones are not going to solve this problem. In fact, they will make it worse, because it will encourage Maliki to believe there is a military solution to this problem, and that is what perpetuates civil wars,” said Kenneth Pollack of the Brookings Institution in Washington.

A three-way conflict

The latest violence erupted after Maliki dispatched troops last week to break up a year-old protest camp in Anbar’s capital, Ramadi, where Sunnis had gathered to air grievances against the government.

The upheaval that followed has evolved into a complicated three-way conflict in which almost all Sunnis have turned against the central government, though some have aligned themselves with militants from the al-Qaeda-linked Islamic State of Iraq and Syria and others have not.

In Ramadi, local tribesmen have been fighting the militants and have ousted them from most of the areas they had seized.

(The Washington Post)

But Monday, the advances stalled, and al-Qaeda fighters remained dug in in three neighborhoods on the outskirts of the city, residents said. The Iraqi army, demoralized and running short of supplies, has proved unable to dislodge the militants, and the ad hoc tribal militias confronting them lack weapons and ammunition, said retired Brig. Gen. Hassan Dulaimi, a former deputy police chief in Ramadi who is working with the tribal forces battling the al-Qaeda fighters.

“The Iraqi army is not up to standard,” he said. “Their morale is low, and they are not capable of street fighting, while the tribes are willing to die to keep the Iraqi army out of their towns.”

Anger against Maliki

Few support the militants from the Islamic State of Iraq and Syria who have claimed control of Fallujah, a local journalist said. But most don’t dare turn against al-Qaeda, he added, while also having no wish to allow Iraqi security forces back into the city after years of perceived discrimination and abuses by the government.

A resident who has participated in protests against the government sought to play down the role of the al-Qaeda-affiliated militants.

“We are all rebels against Maliki,” he said, adding: “Our goal is to liberate the whole of Iraq from Maliki, his militias and the Safavids,” a reference to Iran, whose government has a close relationship with Maliki.

After years of some of the bloodiest fighting of the Iraq war, the United States managed to quell al-Qaeda in Anbar by arming and funding local tribes against the militants. But Maliki neglected to sustain the relationships forged by American troops and instead embarked on a campaign of arrests, harassment and persecution of his Sunni opponents.

Since 2011, the war in neighboring Syria has compounded security troubles in Iraq by creating an atmosphere of lawlessness that has allowed al-Qaeda space to organize, train and recruit just across the border. In April, the group’s Iraq affiliate renamed itself the Islamic State of Iraq and Syria, signaling its expanded ambitions and reach, and it has since redoubled its efforts, seizing territory in Syria and embarking on an intensified campaign of bombings against mostly Shiite targets in Iraq.

Nationwide elections due in April have served only to heighten tensions and may have given Maliki further incentive to confront Sunnis, said Toby Dodge, a professor at the London School of Economics.

“Maliki is running an increasingly overt sectarian election campaign, and this is a part of it,” Dodge said. “Maliki needs to solidify the Shiite vote before the election, and the bigger the al-Qaeda threat, the better the chance he has of doing that.”

Ahmed Ramadan contributed to this report.