AKIPRESS.COM - So-called Islamic State (IS) has blown up the Great Mosque of al-Nuri in Mosul, BBC reported Iraqi forces as saying.

The ancient landmark with its famous leaning minaret was where IS leader Abu Bakr al-Baghdadi proclaimed a "caliphate" in 2014.

However, IS claims that US aircraft destroyed the complex, in a statement issued by its news outlet Amaq.

Iraqi Prime Minister Haider al-Abadi said blowing up the mosque was "an official declaration of defeat" by IS.

Aerial photos show that the mosque and minaret has been largely destroyed.

The Iraqi commander in charge of the offensive to retake Mosul said troops were within 50 metres of the mosque when IS "committed another historical crime".

A senior US commander in Iraq said 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," Maj Gen Joseph Martin said.

The jihadists have destroyed a string of important heritage sites in Iraq and Syria.