Sky's Sam Kiley has the latest on the battle for Mosul

More than 500 families have been turned into human shields.

Hundreds of detainees are forced to live alongside possible targets in Mosul, where heavily armed fighters lurk on street corners.

And that's just what's above ground - ahead of an imminent push to liberate the northern Iraqi city of 1.5 million people.

Judging by what is being discovered in village after village captured from the so-called Islamic State (IS), another battle field is being carved beneath the earth not far from Mosul.

At the entrance to Bartella - a Christian town secured after five days of intense fighting - is a gantry hung above a hole some 30 feet deep and ten feet across.


Just short of the bottom, a circular hole leads to a tunnel heading back towards the main road.

"The Kurds have found a whole village like that - houses all linked underground by tunnels and all of the tunnels stuffed with explosives," said a Kurdish colleague in touch with friends on the front line, 15 miles north at Bashiqa.

"The whole place was rigged to go up."

Inside a town liberated from Islamic State fighters

Mosul - intelligence sources have indicated - may be similarly hollowed out and primed.

The once multi-cultural city on the Tigris was captured over two years ago by IS.

Now, it may be rigged for horror.

There are reports, already, of mass executions of more than 280 local people, including children.

They had somehow angered the cult.

Its membership, meanwhile, has been reinforced with foreign fighters glowing with the prospect of martyrdom.

Bartella is badly smashed up.

There are no signs of bodies but the burning buildings and bullet holes, the characteristic dandelion-shaped splashes made by rocket propelled grenades when they hit walls, and the wires - wires everywhere - tell of a bitter fight through a booby-trapped maze.

The local Syrian Orthodox church is still standing.

But another nearby was flattened. Its congregation fled, or was murdered, when the town fell.

Religious icons sold in its shop were scattered on the floor along with pictures of children in a choir.

Did those youngsters survive? And if so, where are they now?

Image: The Orthodox church shows the signs of fire

The families being used as shields in Mosul against coalition bombing are Christian, sources in the city claim.

Perhaps those children from Bartella are among them.

As we move around the town, there is so much broken glass it crunches underfoot.

Tombs have been forced open and robbed, ancient manuscripts destroyed or, more often, sold into the black market.

And all to fund a cult that thinks it has the right to call itself an Islamic Caliphate.

Previous Caliphates ruled the Middle East, North Africa and much of Spain.

This ersatz version believes it's been established to conduct a final battle that will hasten the arrival of the End Time around the town of Dabiq, in northern Syria.

The "Caliphate" inconveniently lost that to Syrian rebels a couple of weeks ago.

One can only hope, or even pray, that the jihadists have not decided that their Armageddon can be met in Mosul.