Ten years after Sunni extremists blew up a revered Shiite shrine, igniting the worst sectarian violence Iraq had ever seen, the country remains deeply divided, with the Islamic State group facing off against increasingly powerful Shiite militias.

The rebuilt golden dome of the al-Askari shrine rises above the low, brown skyline of Samarra, but down below a maze of blast walls and checkpoints manned by Shiite militiamen separate pilgrims from the city's mostly Sunni residents. The IS group's lightning advance across northern and western Iraq in 2014 stalled just outside Samarra, though the front lines are now some 30 kilometers (20 miles) away.

Many believe IS would have never emerged if al-Qaida in Iraq -- a precursor of the extremist group -- had not blown up the shrine in the early hours of Feb. 22, 2006, shattering its golden dome and setting off a two-year wave of reprisal attacks.

Shiite lawmaker Muwaffak al-Rubaie, who was then Iraq's national security adviser, remembers the call he got from a local security official that morning. "He said today is the day of judgment," al-Rubaie recalled. "He was absolutely right."

In the days that followed, hundreds of Sunni mosques were attacked and thousands of civilians were killed. As Sunni extremists carried out near-daily suicide bombings, Shiite militiamen raided Sunni neighborhoods, abducting young men, torturing and killing them, and dumping the bodies in the streets.

In 2006 alone, the United Nations estimated that more than 34,000 civilians had been killed across Iraq. The following year, the government withheld casualty figures from the U.N., fearing they would be used to paint a "grim" picture of the country and undermine security efforts.

Baghdad's once-mixed neighborhoods were carved into Sunni and Shiite enclaves that soon came to be surrounded by high concrete walls and concertina wire. In a country where mixed marriages were once common, merely having a Sunni or Shiite first name was enough to be disappeared at one of innumerable flying checkpoints.

Iraqi security forces backed by a surge of tens of thousands of U.S. troops were eventually able to halt the bloodletting by 2008, but the country has never been the same.

"The wounds that were created then have healed, but with permanent scars," al-Rubaie said.

The lingering animosity can be seen in the shadow of the rebuilt shrine, where Sunni residents who once prided themselves on being its guardians now live under a permanent security lockdown. Streets that once thronged with pilgrims are empty, and shops that catered to them are shuttered.

Saad Eskander, an Iraqi historian and former director of the National Archives, said that as the only Shiite shrine located in a Sunni-majority city, the site was a symbol of coexistence for centuries. A Shiite Muslim, he remembers praying there alongside Sunnis as a child.

But he says that in the aftermath of the 2006 attack, politicians exploited popular anger for their own ends. Years of sectarian politics paved the way for the emergence of IS, and led many Sunnis in Iraq to initially welcome the extremists as liberators.

"Daesh is a result of those sad events," he said, using an Arabic acronym for the group.

"Before 2006, the divisions in Iraq were between the political representatives of the two communities," Eskander said. "Now the divisions are between the two communities themselves."

Thousands of pilgrims still visit the shrine every day, but they are channeled through a labyrinth of walls that separate them from Sunni neighborhoods. Sunni residents must pass through checkpoints manned by Shiite militiamen, who took over security after Iraq's army and police crumbled in the face of the IS advance.

Aruba, a 30-year-old Sunni woman who works in a pharmacy, said her parents used to regularly visit the nearby shrine before the U.S.-led invasion in 2003, and recalls going there herself as recently as 2005. But she doesn't know of a single Sunni resident who has been since 2006.

"They don't respect that this is where I come from," Aruba said of the forces guarding the shrine. "They search me in my own home." She asked that her last name not be published out of concern for her safety.

"This place belongs to us," said Abdul Rahman Salah, a customer at the pharmacy. "The shrine's Imam was our grandfather."

The shrine is the final resting place of the 10th and 11th imams, religious figures from the 9th century who most Shiites believe inherited the mantle of leadership from the Prophet Mohammed. The adjacent mosque is built on the site where the 12th imam, who most Shiites believe will return as a messiah-like figure, disappeared more than 1,000 years ago. Millions of pilgrims visit every year.

Salah said that before 2006, Samarra residents looked after the shrine and handled security, even worshipping alongside the mostly Shiite visitors. But after the February attack, the militias moved into the area and brought Shiites from neighboring villages to maintain the grounds.

In the following years, while money poured in to rebuild the shrine, the local economy withered as pilgrims no longer ventured out into the city.

"I don't even want to look at that site anymore," Aruba said. She said she views it as a symbol of the Shiite-led government's neglect of Sunni communities.

Naji Sayad, a member of the so-called Peace Brigades, the Shiite militia that guards the site, acknowledges that the city seethes with resentment.

"Honestly, they don't want us here, they say take your shrine and just leave," he said. "The people of Samarra, they used to survive on the people who visited the shrine... But because they attacked it in 2006, this doesn't belong to them anymore."

___

Associated Press writer Ali Hameed contributed to this report.