BAKHDIDA, Iraq — In the center of this hardscrabble Christian town there's a 12th-century church where visitors can peer into an underground passageway that once allowed the faithful to hide from Muslim marauders.
The tunnels below have since crumbled, but the threat still looms on northern Iraq's surrounding plains.
When advancing Islamic State militants launched mortar attacks in late June, nearly all of Bakhdida's 50,000 residents fled overland to Irbil, the capital of the Iraqi region of Kurdistan, for protection. Were it not for Kurdish pesh merga forces that swept in to beat back the onslaught, this historic Christian enclave, known to locals as Qaraqosh, would be deserted.
In recent days, most people have come back to their homes. But dire water and fuel shortages, electrical blackouts and a lack of work are strangling returnees who must also grapple with the mental strain of living within firing range of al-Qaida-inspired Sunni jihadists.
With Iraq at risk of fracturing along sectarian fault lines, local leaders fear the loss of one of the world's oldest Christian communities and its heritage as more and more residents move to Kurdish cities and neighboring countries. On Friday, the exodus was accelerated when the Islamic State decreed that Christian holdouts in the city of Mosul must convert to Islam or pay a special tax — with death as a "last resort."
"Bags are packed; people are leaving for good because it's almost impossible to live here right now," said Louis Marcus Ayub, 54, a Syrian Catholic member of the Bakhdida city council. "If there is no political solution, we're in danger of disappearing."
Iraqi Christians have endured greater persecution since the 2003 U.S. invasion that toppled Saddam Hussein. In the sectarian conflict that followed, a surge of harassment, church bombings and other deadly attacks caused the population to shrink from 1.5 million to about 400,000.
In 2008, a wave of violence targeted Christians living in Mosul, Iraq's second-largest city and an ancient hub of Christianity in the region. Without a militia of their own, thousands found safe haven in Bakhdida, about 19 miles to the southeast.
When Islamic State militants staged a lightning attack June 10 on Mosul and took over the city, fresh waves of Christians fled to Bakhdida; only this time, militants stayed on their heels. In less than 48 hours, a flurry of mortar rounds and stories of kidnapping and murder of their co-religionists in Syria combined to empty the town.
"They want to kill us," said Martin Jameel, 25, a shopkeeper who had just come back from Ainkawa, a Christian suburb of Irbil full of displaced families, to check on his goods. "We have no oil, no weapons. We are not Muslims, so they think we are enemies."
The Syrian Catholic Archbishop of Mosul, Yohannna Petros Mouche, was one of the few who stayed behind. He understood that many families had left "to lead dignified lives," but he's resolved not to go.
"If we all leave, it sends the message that there is nowhere safe for Christians to live in Iraq — and this worries me," he said, gripping the pewter cross that hung heavy from his neck.
"I'm not a vagabond. This is my home, and I will die here if necessary."
The seminary he overseas in Bakhdida had already become a way station for 35 Christian families and clergy from Mosul. According to Father Amanoel Adel Kalloo, one of the displaced, the city's Christian community has plunged from about 3,000 to between 200 to 300 since the Islamic State takeover.
On two trips back to the city to collect belongings, he saw that the homes of religious leaders had been ransacked and taken over by militants, he said.
Muslims renting property from Christians have been ordered to pay the Islamic State instead, and employers have been told to lay off all Christian workers. For the first time in 1,600 years, there is no Sunday Mass.
While lives have so far been spared, Kalloo said the early July disappearance of two women who ran an orphanage, along with three children under their care, has stoked anxieties. He believes the rebel group was behind the abduction, but no one has yet received any information on their condition or whereabouts.
In Bakhdida, residents are grateful to Kurdish forces that have established a security perimeter around the city, allowing some breathing room for people to return. The Kurds have since outfitted a local Christian "protection committee" with bulletproof vests and assault rifles to patrol the streets.
No hostilities have been exchanged in more than two weeks, but if Islamic State militants go on the offensive again, "we will defend them (the Christians) until the last drop of blood," vowed Capt. Mohammad Kamal Nader, a pesh merga officer in charge of the security at the town's main checkpoint. "It is our duty."
For now, the overwhelming concern is water. Area taps have run dry since the Islamic State took Mosul and cut off the town's Tigris River water supply amid 100-degree-plus temperatures.
All water now has to be trucked in from outside at great expense.
Adding to people's woes are electricity blackouts for the better part of each day. The main hospital is short of doctors who have stopped coming from Mosul. And without funds to pay town employees, heaps of garbage are piling up along sidewalks that remain largely empty throughout the day.
Bashar Toma, a 50-year-old mason, was among those preparing to leave. Last month, a pair of Islamic State mortars crashed onto the roof of the six-bedroom home Toma had painstakingly built to accommodate his children.
He thanked God that no one was hurt. But the constant psychological stress of living less than three miles from an aggressive and well-armed rebel force — whose forward positions are visible from his roof — has become too much to bear for the lifelong resident.
In the morning, Toma would move his family to a cramped apartment in Irbil.
"It hurts my heart to leave," he said, "but I fear it will only get worse here."