Tunnels to Mosul's secret palace revealed: Hidden passages to 2,600-year-old shrine are found buried under the ruins of an 'idolatrous' mosque blown up by ISIS as images also emerge of wrecked museum

US-backed Iraqi forces have discovered a secret network of tunnels dug by ISIS under Mosul's ancient Mosque of Jonah in a bid to preserve artefacts for loot.

The Islamist extremists seized the shrine when they stormed through northern Iraq three years ago, bulldozing and dynamiting ancient sites and smashing statues and sculptures.

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Jonah's mosque was blown up in July 2014, but experts surveying the damage after it was recaptured in January found the tunnels leading down to a 7th century BC Assyrian palace.

Separately US-backed Iraqi forces discovered a secret network of tunnels dug by ISIS under Mosul's ancient Mosque of Jonah

The jihadis had carefully carved out the tunnels, pictured, in a bid to preserve artefacts for loot

The ultra-hardline Islamists seized the mosque when they stormed through northern Iraq three years ago

Jonah's mosque was blown up in July 2014, but experts surveying the damage after it was recaptured in January found the tunnels, pictured above, leading down to a 7th century BC Assyrian palace

They are still lined with broken segments of pottery as well as sections of stone panel with carved figures and text.

The careful way they were dug show the militants wanted to keep the treasures intact, said archaeologist Musab Mohammed Jassim.

He continued: 'They used simple tools and chisels to dig the tunnels, in order not to damage the artefacts.'

The digging 'was carried out according to a plan and a knowledge of the palace'.

The careful way they were dug show the militants wanted to keep the treasures intact, according to archaeologists

The mosque is built over the reputed burial site of the biblical prophet revered by Jews, Christians and Muslims -- who know him as Nabi Yunis

The secret tunnels are still lined with broken segments of pottery as well as sections of stone panel with carved figures and text

While Islamic State's 30-month occupation of the Mosque of Jonah left a legacy of damage and theft, it has also opened up fresh opportunities for archaeologists.

Excavations which were launched in 2004, the year after the US-led invasion of Iraq, revealed an entrance to the palace of Assyrian king Esarhaddon.

But work halted shortly after because it threatened the foundations of the mosque, built over the reputed burial site of the biblical prophet revered by Jews, Christians and Muslims -- who know him as Nabi Yunis.

Jassim said: 'The whole palace remained untouched by the experts and foreign excavation.

'So this site, the Esarhaddon Palace, maintained all its features. It contains large collections of sculptures of different sizes and shapes and valuable artefacts'.

They have carried out a campaign of cultural destruction -- bulldozing and dynamiting ancient sites as well as smashing statues and sculptures

Archaeologist Musab Mohammed Jassim said: 'They used simple tools and chisels to dig the tunnels, in order not to damage the artefacts'

The digging 'was carried out according to a plan and a knowledge of the palace', the archaeologist added

The ISIS occupation of the Mosque of Jonah left a legacy of damage and theft but it has also opened up fresh opportunities for archaeologists to survey the remaining artefacts

Excavations which were launched in 2004 after the US-led invasion of Iraq revealed an entrance to the palace of Assyrian king Esarhaddon. But work halted shortly after because it threatened the foundations of the mosque

The mosque 'contains large collections of sculptures of different sizes and shapes and valuable artefacts', according to archaeologists

The mosque had 'remained untouched by the experts and foreign excavation' until it was dug out by ISIS militants

Shocking pictures released today show the ravaged remains of Mosul's museum which has been looted and destroyed by evil Islamic State jihadis.

Militants filmed themselves smashing up ancient artefacts inside the building which is now strewn with rubble.

The large stone wing of a statue of lamassu -- an Assyrian winged bull deity -- is seen lying on the dusty floor among other broken remnants of the past.

After it was invaded by jihadis here is now a gaping hole in the floor of the rubble-strewn museum in Mosul, pictured above

A block engraved with Arabic Islamic calligraphy, pictured above, lies on the floor smashed to pieces

Iraq's elite Rapid Response Unit captured the museum from ISIS control just days ago. They found a building littered with rubble with most of the artefacts gone

Lieutenant Colonel Abdel Amir al-Mohammedawi, who is part of Iraq's elite Rapid Response Unit, said: 'What they didn't loot they destroyed'

A block engraved with Arabic Islamic calligraphy lies close by, and some Islamic manuscripts have been left undamaged. But almost everything else has gone.

Iraq's elite Rapid Response Unit captured the museum building from ISIS control just days ago.

Lieutenant Colonel Abdel Amir al-Mohammedawi, who is part of the force, said: 'What they didn't loot they destroyed.'

Dozens of Assyrian, Akkadian, Babylonian, Persian and Roman artefacts that the ransacked museum held have been stolen or damaged.

'Some were smuggled out of Iraq,' Mohammedawi said.

Dozens of Assyrian, Akkadian, Babylonian, Persian and Roman artefacts held in the ransacked museum have all been stolen or damaged, such as the texts pictured above

Islamic State jihadis even filmed themselves smashing some of the building's contents including priceless statues, pictured above, with sledgehammers

The destruction was part of their highly publicised campaign to erase Iraq's cultural history

Islamic State jihadis filmed themselves smashing some of the building's contents including priceless statues with sledgehammers in 2015.

It was part of their highly publicised campaign to erase any cultural history that contravenes their extreme interpretation of Sunni Islam.

But they have also used the antiquities as a source of income.

The efforts to avoid damaging some antiquities contrast with the destruction of ancient sites across Islamic State's self-declared caliphate in Syria and Iraq.

A US-backed campaign dislodged Islamic State from most Iraqi cities captured in 2014 and 2015 -- including parts of Mosul, pictured above, where the museum is located

The building, pictured above, was severely damaged by evil Islamic State jihadis and the ongoing fighting in the area

The outside of the museum, which features Roman-style columns, pictured above, has now been blackened from shell or rocket blasts and peppered with bullet holes

The United States has said the looting and smuggling has been a significant source of income for the militants.

In July 2015, American authorities handed Iraq a hoard of antiquities it said it had seized from Islamic State in Syria.

A US-backed Iraqi campaign dislodged Islamic State from most Iraqi cities captured in 2014 and 2015.

The militant group is now fighting in its last major urban stronghold, in the western part of Mosul, where the museum is located.

Iraqi troops dusted off some of the historical stone slabs lying on the floor in the museum, which is scattered with fragments of rubble

Tables from the museum which one day would have held dozens of historical artefacts now lay smashed to pieces and covered in dust

Fragments of shattered glass can also be seen on the tables, above left, while piles of stone show the trail of destruction left by jihadis in the building

The outside of the building, which features Roman-style columns, is blackened from shell or rocket blasts and peppered with bullet holes.

A Chaldean Catholic church next to it has also been mostly gutted, its altar cracked down the middle.

The body of an Islamic State fighter lay just outside the church on Saturday, days after the fighting had moved further forward.

Iraqi troops dusted off some of the historical stone slabs lying on the floor in the museum, which lies just outside Mosul's old city -- one of the final Islamic State strongholds in Mosul.

Barely any of the Mosul museum's treasures remain with its shelves gutted and the archives ransacked

However the evil jihadis left some artefacts behind such as this stone, pictured above, covered in Arabic script

WHO IS PROPHET JONAH OR 'YUNIS'? ISLAMIC AND CHRISTIAN VERSIONS The Prophet Yunis is widely regarded as the Islamic version of the prophet perhaps more commonly referred to in the Bible as Jonah.

Jonah was famously swallowed by a whale or a fish, depending on the literature, and his Islamic narrative has some similarities as well as substantial differences to the Hebrew Bible story.

The Quran describes Jonah as a righteous preacher of the message of God but a messenger who, one day, fled from his mission because of its overwhelming difficulty.

The Quran says that Jonah made it onto a ship but, because of the powerfully stormy weather, the men aboard the ship suggested casting lots to throw off the individual responsible.

The Prophet Yunis is widely regarded as the Islamic version of the prophet perhaps more commonly referred to in the Bible as Jonah

When the lots were cast three times and Jonah's name came out each time, he was thrown into the open ocean that night.

A gigantic fish came and swallowed him, and Jonah remained in the belly of the fish repenting and glorifying God.

The Christian version of the story goes that a huge storm arises and the sailors, realising it is no ordinary storm, discover Jonah is to blame.

Jonah admits this and tells them if he is thrown overboard, the storm will cease.

The sailors try to dump as much cargo as possible before giving up, but feel forced to throw him overboard, at which point the sea calms.

The sailors then offer sacrifices to God.

Jonah is miraculously saved by being swallowed by a large fish in whose belly he spends three days and three nights.

While in the great fish, Jonah prays to God in his affliction and commits to thanksgiving and to paying what he has vowed.

God commands the fish to spew Jonah out.