The United States and Iraq said ISIS blew up a historic mosque in Mosul that was the ideological heart of the terror group and the birthplace of its self-declared caliphate. ISIS, through its news agency, said US warplanes were responsible for the loss late Wednesday of the Great Mosque of al-Nuri and its leaning minaret.

US officials told CNN the ISIS claim was "1,000% false." Iraq Prime Minister Haider al-Abadi said the ISIS act amounts to "an official announcement of their defeat." His military commanders said militants blew the mosque up after troops closed in. It's difficult to overstate the symbolism of the Old City mosque that has witnessed fierce fighting between ISIS militants and coalition forces determined to liberate what was the country's second-largest city.

For years, the militant group's black and white flag fluttered from the minaret, which has risen over the city for 800 years. Now the site has largely been reduced to rubble. On July 4, 2014, ISIS leader Abu Bakr al-Baghdadi led Friday prayers in the mosque. 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.

It was the first and last time the leader of the terrorist group spoke publicly to his followers. The mosque's imam had been executed about a month earlier for refusing to join ISIS, according to the United Nations. CNN's Arwa Damon said Baghdadi's declaration effectively broke down borders between Syria and Iraq, creating a magnet for foreign fighters wanting to join ISIS' cause.

The Islamic complex has been very much on the mind of the Iraqi forces, who believed taking control of the mosque would be a highly symbolic victory. Federal police earlier this year said they looked forward to praying in al-Nuri -- but the resistance continued.

Courtesy: CNN