Iraq's second city, and other areas retaken from Iraq, need more than a military strategy.
The mosque was used by the group's leader Abu Bakr al-Baghdadi to declare a caliphate in 2014.
With less than 1,000 militants left to defend its shrinking pocket of control in Mosul, the Islamic State group faces total defeat by the Iraqi army and allies.
The Iraqi army's chief of staff said the Islamic State group (ISIS) only controlled 3.8 percent of Iraq.
Militants disguised themselves as Iraqi security forces to gain the trust of civilians and soldiers before executing them.
The U.S. approved $295.6 million in military assistance for Kurdish peshmerga units in Iraq as they prepare for a joint anti-ISIS offensive with allied Shiite Muslim militias.
The Islamic State militant group launched two poison gas attacks on Iraqi troops in two days as pro-government forces advanced against the jihadists in their final Iraqi stronghold of Mosul.
U.S. military advisers have begun dressing like their Iraqi counterterrorism allies in order to blend in and better coordinate with local forces fighting the Islamic State group in Mosul.
Iraqi PM Hiader al-Abadi said it would take three more months to rout ISIS.
The head of the anti-ISIS coalition said removing ISIS from Raqqa will take longer than Mosul.