IS destroys Mosul mosque where it declared 'caliphate'

The Islamic State has destroyed an iconic 12th-century mosque in the city of Mosul that was the ideological heart of the terror group and the birthplace of its self-declared caliphate.

Iraqi Prime Minister Haider al-Abadi on Thursday said the destruction of the Great Mosque of al-Nuri and its leaning minaret is "an official declaration of defeat" by the IS, Efe news reported.

"Blowing up the al-Hadba minaret and the al-Nuri mosque amounts to an official acknowledgement of defeat," Al-Abadi said.

Iraqi forces said IS militants blew up the ancient mosque and its famous leaning minaret on Wednesday as jihadists battled to stop advancing pro-government troops.

It was from this mosque three years ago that the militants' leader Abu Bakr al-Baghdadi declared the terror organisation's so-called caliphate in July 2014.

The IS claimed that American aircraft had destroyed the complex, a claim denied by the US, BBC reported.

Aerial images provided by the international coalition showed that the mosque complex lay almost entirely in ruins.

The mosque's destruction prompted condemnation, with the senior US commander in Iraq saying that IS had destroyed "one of Mosul and Iraq's great treasures".

"This is a crime against the people of Mosul and all of Iraq, and is an example of why this brutal organisation must be annihilated," Major General Joseph Martin said.

Iraqi joint operations commander, Major General Abdel Amir Yarallah, described it as "another historical crime" committed by the IS.

Iraq's military said they were on the cusp of capturing the complex just hours before the explosion.

The al-Nuri mosque dated back to 1172 and was Mosul's most famous Sunni mosque. It was named after the Muslim leader, Nur al-Din Mahmoud Zangi, famous for waging jihad against Christian crusaders.

Its 45-metre cylindrical leaning minaret was nicknamed "the hunchback" and during the final three years of its 800-year existence it remained under IS control.

The black flag of the IS, which sat atop the minaret, became a geographical referencing point for the Iraqi coalition troops who have been slowly advancing into the ancient Iraqi city to flush out the IS.

In 2012, the United Nations cultural organisation UNESCO signed an agreement with Iraqi authorities to begin restoration works on the minaret but the project was abandoned when two years later the IS swept to power in Mosul.

Mohammed al-Bayati, the head of the Nineveh regional security committee estimated that the operation to conquer IS in Mosul would be completed within a week due to the group's steady decline.

The effort to reclaim Mosul from IS began in October 2016 and earlier this week saw the start of a final push by the Iraqi Army and its allies against the jihadists.