Abandoned villages on road to Mosul rigged with tunnels and bombs

A deep tunnel, booby trapped with an improvised explosive device, burrows under houses at the entrance to the village. Nearby, an anti-personnel mine lies half buried in a dirt road.

Residents began returning on Wednesday to the village of Sheikh Amir on the road to Mosul, recaptured overnight by advancing Kurdish fighters in the early days of the biggest advance that has been launched against Islamic State.

They found a village rigged with explosives and dug in with elaborate underground defences, abandoned by the Islamists who have retreated closer to Mosul, 30 km (19 miles) to the west.

Three days into the assault began on Mosul, U.S.-backed government and Kurdish forces are steadily recovering outlying territory before the big push into the city itself, expected to be the biggest battle in Iraq since the 2003 U.S.-led invasion.

Much of Sheikh Amir had been torn down, including the house of Abbas Ahmad Hussein, a 36-year-old resident who fled the village when Sunni militants of Islamic State, also known as ISIL, ISIS or Daesh, captured it in 2014.

A Shi'ite, he returned on Wednesday to survey the damage with a small truck to take out any salvageable items, but found nothing left to save amid the wreckage.

"I spent all my money to build this house and Daesh destroyed it," he said. "My brother, my uncle and my cousins live around here and they destroyed all their houses too. They destroyed all the houses belonging to the Shi'ites."

Nearby, red graffiti had been sprayed on a house: "Shi'ites are non-believers."

The village had a mixed population before Islamic State arrived, but Shi'ite houses were destroyed by the militants who consider all Shi'ites infidels who must convert or die.

Mosul, the last major stronghold of Islamic State fighters in Iraq, is five times the size of any other city the militant group has held. Recapturing it would deal a decisive blow to its self-declared caliphate.

But the booby trapped bunkers dug underneath this village, as well as the sectarian invective sprayed on its walls, show how difficult the advance may be. Tens of thousands of pro-government troops will face a tenacious enemy that has had years to prepare and a history of using human shields. A population of some 1.5 million civilians will be in harm's way.

SHI'ITE MILITIA TO JOIN FIGHT

This part of northern Iraq is among the most diverse in the country, with many ethnic and religious groups fearful of revenge attacks and worried about the balance of power once Islamic State fighters are chased away.

In an announcement that could alarm some Sunni civilians in the path of the fighting, a powerful Shi'ite paramilitary force said it would support the Iraqi army's offensive by helping secure a town located on one of the main routes out of Mosul.

The Popular Mobilization Force (PMF), a coalition of mostly Iranian-trained militias, said late on Tuesday it would back government forces advancing towards Tal Afar, about 55 km west of Mosul. [nL8N1CP16F]

The PMF includes thousands of battle-hardened fighters with powerful political allies in Baghdad. They have been accused of carrying out killings and kidnappings in other areas freed from Islamic State, although they deny such abuse is pervasive.

Iraqi officials want to keep them off the main battlefields in Mosul to avoid alarming Sunni Muslim residents.

Taking Tal Afar would in effect cut off the escape route for militants wanting to head into neighbouring Syria and would please the Iran-backed army of Syrian President Bashar al-Assad, which accuses the U.S.-led anti-Islamic State coalition of planning to allow the jihadists such a safe passage.

But it could also hamper the escape of civilians from Mosul, who must be persuaded that it is safe to leave.

Iraqi Prime Minister Haider al-Abadi said on Tuesday that blocking the road to Syria was the responsibility of the coalition that is providing air and ground support to Iraqi and Kurdish troops engaged in the battle. [nL8N1CO587]

Tal Afar's pre-war population of 150,0000 to 200,000 was a mix of Sunni and Shi'ite ethnic Turkmens until Shi'ites fled the town after Islamic State arrived.

"The Iranians and the (PMF) plan to take Tal Afar because of the Shi’ite significance and use that as a way to angle in to Mosul," said a senior Iraqi official who asked not to be named. "But they also want to use it as a way to angle into the Syria fight."

SECTARIAN DIVISIONS

U.S. President Barack Obama said on Tuesday it would be a difficult fight but Islamic State "will be defeated in Mosul". He hopes to bolster his legacy by seizing back as much territory as he can from Islamic State before he leaves office in January.

A total of 20 villages were taken from the militants east, south and southeast of Mosul by early Tuesday, according to statements from the two forces.

Islamic State said on Monday its fighters had targeted the attacking forces with 10 suicide bombs and that their foes had surrounded five villages but not taken them. None of the reports could be independently verified.

In Washington, Pentagon spokesman Captain Jeff Davis told reporters on Tuesday that it was known that civilians in Mosul were being used as human shields.

Iraqi government forces are mostly fighting south of Mosul and were trying on Wednesday to clear the region of Shora, 40 km (25 miles) south of the city, a military statement said. Kurdish Peshmerga fighters were deployed on the eastern and northern frontlines, 20 to 25 km from the city.

"The PMF will be backing the security forces on the western front (..) along two axes. The first is Tal Afar and the second is to support the forces going into the centre of Mosul," a statement on the PMF website said.

Iraqi officials and residents of Mosul say Islamic State is preventing people from leaving the city but civilians are fleeing from outlying districts and villages.

The United Nations says that in a worst case scenario 1 million people could be displaced by the Mosul campaign, requiring emergency housing and food. It has warned that some 100,000 people may arrive in Syria from the Mosul area.

Still, most of the people from the area say they are waiting only for the fighting to end so that they can come home.

In Sheikh Ahmed, around the corner from the ruined house of Shi'ite villager Abbas Ahmad Hussein, a 47-year-old Sunni shepherd named Ali had also returned to check on his house.

It was relatively intact although some items had been stolen, he said.

"When I came to the edge of the village I didn't want to come in," he said. "I was shocked by the destruction. It made me sick."

Asked if Shi'ites and Sunnis could live together in the village again the future, Ali said: "Inshallah" (God willing).

"I have more Shi'ite friends than Sunni friends," Ali said. "Daesh is a threat to all humanity."