However, Isis themselves put out a statement claiming it had been destroyed in a coalition airstrike.
"The Coalition is working by, with, and through the government of Iraq to defeat ISIS in Mosul and throughout Iraq".
In late June and early July of 2014 ISIS sought to establish itself as more than just an Islamist extremist group in Iraq and Syria and give itself legitimacy as a "caliphate". Now the site has largely been reduced to rubble. Shrouded in a black turban and robes, the cleric declared the founding of a new caliphate and called on fellow Sunnis to carry out a holy war.
"An estimated 50,000 children are in grave danger as the fighting in Mosul enters what is likely to be its deadliest phase yet", Save the Children said Sunday night in a statement. The area of the mosque is expected to be liberated soon as security forces are closing in.
A coalition spokesman, U.S. Army Col. Ryan Dillon, told The Associated Press that coalition aerial surveillance confirmed the mosque was destroyed, but he said a U.S. strike was not the cause.
In a failed effort to break the Iraqi army's siege, ISIS on Wednesday launched a wide-scale counterattack on the Iraqi army to break out of the Old Mosul district, where they are surrounded by Iraqi forces.
The situation in Mosul has been desperate.
"The minaret of Al-Hadba has been here forever, it is part of the history of Mosul, it is the symbol of the city", Ahmed Thilij Hamed, a 49-year-old resident of a neighbourhood near the Old City, told AFP on Monday.
Damon said about 100,000 terrified civilians remain in the convoluted battlefield.
IS has blamed a USA strike for the mosque's destruction.
American military officials deplored the destruction.
The Al Hadba Minaret has been leaning about 253 centimeters (a little more than 8 feet) off its axis for several years and the United Nations Educational, Scientific and Cultural Organization in 2012 announced plans to help come up with a plan to stabilize it, the group said. "This is just another example that ISIS is a cruel, heartless and god-less ideology that can not be permitted to exist in the world".
Islamic State fighters have destroyed many Muslim religious sites, churches and shrines, as well as ancient Assyrian and Roman-era sites in Iraq and in Syria.