ISIS militants yesterday blew up the iconic Grand al-Nuri Mosque of Mosul, in a move the Iraqi prime minister called a declaration of 'defeat' for the jihadist group.

The mosque, and its famous 'hunchback' al-Hadba minaret (tower structure) were destroyed at 9:35pm local time on Wednesday, the Iraqi military said. The 12<sup>th century mosque is the same one from which ISIS leader Abu Bakr al-Baghdadi declared a 'caliphate' across Syria and Iraq three years ago.

Last night the structure was reduced to rubble, to the lament of onlookers.

'Blowing up the al-Hadba minaret and the al-Nuri mosque amounts to an official acknowledgement of defeat,' Iraq's prime minister Haider al-Abadi said on his website.

The ISIS-run channel Amaq news agency said American aircraft were responsible for the destruction, but the US-led coalition combating the group denied the claim.

'We did not strike in that area,' said coalition spokesman US Air Force Colonel John Dorrian.

The coalition's ground commander US Army Major General Joseph Martin said: 'The responsibility of this devastation is laid firmly at the doorstep of ISIS.'

He called the demolition 'a crime against the people of Mosul and all of Iraq, and is an example of why this brutal organisation must be annihilated.'

The destruction came as coalition forces had closed in on the jihadists' stronghold in the Old City of Mosul, the last area in the city under ISIS occupation. Martin pledged continued to support to the Iraqi security force 'as they bring these terrorists to justice'.

ISIS' leader Baghdadi has departed the conflict in Mosul and is now believed in the border area between Iraq and Syria. 

Additional reporting by Reuters