Iraqi troops have captured the iconic mosque in which Islamic State's leader made his only known appearance - a symbolic victory a week after it was blown up by the jihadists.

The 12th century Great Mosque of al-Nuri in Mosul- now lying in ruins - was recaptured on Thursday exactly three years to the day since Isis proclaimed its so-called caliphate and Abu Bakr al-Baghdadi as its chief.

The mosque's famous leaning minaret, which earned the nickname of Iraq's Tower of Pisa, had dominated skyline of Iraq's second city for centuries and is pictured on the country's 10,000 dinar banknote.

After the grand mosques of Mecca and Medina, al-Aqsa in Jerusalem and the Umayyad mosque in Damascus, al-Nuri was one of the great monuments in Islam.

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Footage of the site shows only the base remains, with the rest reduced to rubble.

Maj. Gen. Sami al-Aridi warned the site will need to be cleared by engineering teams as Isil fighters likely rigged it with explosives.

The militant group tried to claim the mosque was hit by a US-led coalition air strike. However, footage later released by the Iraqi army showed several explosions emanating out of the leaning minaret, consistent with the structure having been rigged.

This photo, taken this week, shows an aerial view of the destroyed landmark al-Nuri mosque. Photo / AP
This photo, taken this week, shows an aerial view of the destroyed landmark al-Nuri mosque. Photo / AP

The destruction of the minaret, which took place on the holiest day of the Islamic calendar, Laylat al-Qadr - the moment the Koran was revealed to the prophet Mohammed - shocked Muslims worldwide.

But Iraqi forces had been preparing for the possibility, believing Isis would not allow the troops to score a symbolic victory by reclaiming the mosque where in the summer of 2014 Baghdadi delivered his first and only sermon as leader.

He would declare control over huge swathes of land the size of Britain, across both Iraq and neighbouring Syria.

The recapture of the mosque, more than eight months into the offensive to liberate the city, will offer little relief to Iraqis but is a sign of the quick progress being made in the Old City.

In this file photo is the famous leaning minaret. Photo / AP
In this file photo is the famous leaning minaret. Photo / AP

The operation to take the Old City, where some 50,000 civilians remained trapped, began 10 days ago.

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Officials estimate they have liberated half the ancient part of the city and that the remaining half will be completed in the coming days.

Federal police and elite units of the Counter-Terrorism Service have also been fighting inside the district's maze of narrow alleyways.

The military estimates up to 350 militants are dug in among civilians in wrecked houses and crumbling infrastructure. They are trying to slow the advance of Iraqi forces by laying booby traps and using suicide bombers and snipers.

Sir Michael Fallon, UK Defence Secretary, said on Thursday that Isis is facing its "endgame" in its former Iraqi stronghold in Mosul.

This file photo shows the gate of the Great Mosque or al-Nuri Mosque. Photo / AP
This file photo shows the gate of the Great Mosque or al-Nuri Mosque. Photo / AP

Sir Michael revealed that RAF warplanes have hit more than 700 targets to support the expected imminent liberation of Iraq's second city, where Isis declared its supposed "caliphate" three years ago.

Isis has now lost 70 per cent of the territory it once controlled in Iraq and 51 per cent of the area it held in Syria, meaning more than four million Iraqis and Syrians have been freed from the terror group's tyranny, the Ministry of Defence said.

Speaking ahead of a meeting of Nato defence ministers, Sir Michael said: "Three years on from when Daesh declared its so-called caliphate in Mosul, this evil death cult faces its endgame in the city.

"In Syria, there is now irreversible momentum and progress towards Daesh's defeat in Raqqa, with the SDF (US-backed Syrian Democratic Forces) already controlling nearly 15 per cent of the city."