Iraq's wave of bloodshed has sharply escalated with more than a dozen car bombings across the country, part of attacks that killed at least 95 people and brought echoes of past sectarian carnage and fears of a dangerous spillover from Syria's civil war next door.
The latest spiral of violence - which has claimed more than 240 lives in the past week - carries the hallmarks of the two sides that brought nearly nonstop chaos to Iraq for years: Sunni insurgents, including al Qaeda's branch in Iraq, and Shiite militias defending their newfound power after Saddam Hussein's fall.
But the widening shadow and regional brinksmanship from Syria's conflict now increasingly threaten to feed into Iraq's sectarian strife, heightening concerns that Iraq could be turning toward civil war.
The Shiite-led government of Prime Minister Nouri al-Maliki must balance its close ties with Iran - the main regional ally of Syria's Bashar Assad - and its position among fellow Arab League members and neighbouring Turkey, which strongly back Syria's mainly Sunni opposition.
Al-Maliki appears determined to boost security crackdowns to keep Iraq's minority Sunnis from taking a more high-profile role in the anti-Assad forces, which have received pledges of support from the longtime insurgent group al Qaeda in Iraq.
There have been no claims of responsibility for the current flare-up of violence, capped by the body count on Monday (local time) that was the highest death toll for a single day in 10 months. Yet some analysts believe it's difficult to separate Iraq's deep sectarian suspicions from the Shiite-Sunni split over Assad, which has also led to clashes in Lebanon.
"Iraq now has moved into a bigger circle that covers Syria and Lebanon," said Baghdad-based political affairs analyst Hadi Jalo.
Al-Maliki is not only worried about his Sunni rivals possibly deepening their involvement in the rebel cause in Syria, said Patrick Clawson, director of research at the Washington Institute for Near East Policy. Al-Maliki's worries extend to Iraq's semiautonomous northern Kurdish region, which has close links to Assad foe Turkey.
"Al-Maliki believes this is the time to be tough and show he is in control of the country," said Clawson. "What we are seeing is the backlash to that."
The US and its Western allies strongly support Syria's political opposition, but have been reluctant to significantly boost weapons flow to rebel fighters because of worries over Islamic militants who have joined the anti-Assad brigades. But the deepening refugee crisis in the region, along with concern over spillover violence, is often cited by Arab states and Turkey urging greater Western intervention.
Sectarian tensions have been worsening since Iraq's minority Sunnis began expanding protests over what they say is mistreatment at the hands of the Shiite-led government. Many Sunnis contend that much of the country's current turmoil is rooted in the policies of al-Maliki's government, which they accuse of feeding sectarian tension by becoming more aggressive toward Sunnis after the US military withdrawal in December 2011.
Mass demonstrations by Sunnis, which began in December, have largely been peaceful. However, the number of attacks rose sharply after a deadly security crackdown on a Sunni protest camp in northern Iraq on April 23.
Hours after Monday's stunning blitz of attacks - stretching from north of Baghdad to the southern city of Basra - al-Maliki accused militant groups of trying to exploit Iraq's political instability and vowed to resist attempts to "bring back the atmosphere of the sectarian war".
He also blamed the recent spike in violence on the wider unrest in the region, particularly Syria.
"You cannot remove the Syrian element from what's happening in Iraq," said Sami al-Faraj, director of the Kuwait Center for Strategic Studies. "The outcome of the war in Syria has big consequences for both Iraq's Sunnis and Shiites. What we see now is an extension of that in some respects."
The worst of Monday's violence took place in Baghdad, where 10 car bombs ripped through open-air markets and other areas of Shiite neighbourhoods, killing at least 48 people and wounding more than 150, police officials said.
In Balad, about 80km north of Baghdad, a car bomb exploded next to a bus carrying Iranian pilgrims, killing 13 Iranians and one Iraqi, a police officer said, speaking on condition of anonymity because he was not authorised to brief the media.
Meanwhile, in the predominantly Shiite city of Basra in southern Iraq, twin car bombings - outside a restaurant and at the city's main bus station - killed at least 13 people and wounded 40, according to provincial police spokesman Col. Abdul-Karim al-Zaidi and the head of the city's health directorate, Riadh Abdul-Amir.
"All of a sudden, a thunderous explosion lifted my car and put it back on the ground," said Sami Saadon, a Basra taxi driver who suffered shrapnel injuries in his chest. "I could barely open the door and I crawled outside the car, where smoke and dust were everywhere."
A car bomb later struck Shiite worshippers as they were leaving a mosque in the southern city of Hillah, killing nine and wounding 26, police and health officials said.
Monday's violence also struck Sunni areas.
A car bomb in Samarra, north of Baghdad, went off near a gathering of pro-government Sunni militia waiting outside a military base to receive salaries, killing three and wounding 13. In the western province of Anbar, the hub of Sunni power, gunmen ambushed two police patrols near the town of Haditha, killing eight policemen, officials said.
Also in Anbar, authorities found 13 bodies dumped in a remote desert area. The victims, who included eight policemen kidnapped by gunmen on Friday, had been killed by a gunshot to the head, officials said.
The officials spoke on condition of anonymity because they were not authorised to talk to the media.
The surge in bloodshed has exasperated Iraqis, who have lived for years with the fear and uncertainty bred of random violence.
"How long do we have to continue living like this, with all the lies from the government?" asked 23-year-old Baghdad resident Malik Ibrahim. "Whenever they say they have reached a solution, the bombings come back stronger than before."