Islamic State fighters have so far refused to yield to an ongoing US-backed campaign to drive them from the centre of Mosul, the last key stronghold of the extremist militia in the country, security officials said Sunday.
Security forces were locked in heavy clashes with militants in the heavily populated centre of Mosul after troops came under shelling from an area still under Islamic State control, Brigadier Abdel-Karim al-Sabawi, a senior police officer, told dpa.
"The shelling targeted the [militarized] Federal Police positioned in the liberated area of al-Arbaa Market Square in the centre of Mosul," he added.
Islamic State militants seized Mosul, Iraq's second-largest city, in mid-2014 in a blitz.
On February 19, Iraq started an onslaught to drive Islamic State from the western section of Mosul, almost a month after they had dislodged the extremists from the eastern side of the city.
Mosul campaign chief Abdul Amir Rasheed said he expects the radical group to keep up its 'fierce resistance' to the ongoing offensive to dislodge it from Mosul.
He told Dubai-based broadcaster Al Arabiya that his forces' advance is being slowed down by militants' trademark car bombings, sniper fire and trapped civilians.
Iraqi forces were Sunday trying to recapture a symbolically important mosque in the Old Quarter of Mosul, a day they announced they were around 600 metres from the site.
Al-Nouri Mosque, famous for its leaning minaret, is where Islamic State leader Abu Bakr al-Baghdadi made his only public appearance in July 2014 and promoted his self-styled Islamic caliphate.