Iraqi forces push into Mosul Old City, warn ISIS 'surrender or die'

Iraqi forces began storming the Islamic State-held Old City of Mosul on Sunday, in a final assault on the Islamic State they hope will be the last in the eight-month-old campaign to seize the militants' stronghold, warning civilians to stay inside and telling jihadists to "surrender or die".

Iraqi forces launched the operation Sunday to retake the district, the last part of Iraq's second city still held by ISIS after a months-long offensive.

The historic district, and a tiny area to its north, are the only parts of the city still under control of the Islamists. Mosul used to be the Iraqi capital of the group, also known as ISIS.

The Iraqi army estimates the number of Islamic State fighters at no more than 300, down from nearly 6,000 in the city when the battle of Mosul started on 17 October.

But commanders say the jihadists are putting up fierce resistance and there are fears for more than 100,000 civilians believed to be trapped in the maze of narrow streets, with little food, water or medical treatment.

Staff Major General Maan al-Saadi, a top commander in Iraq's elite Counter-Terrorism Service (CTS), told AFP news agency that heavy fighting had resumed at dawn on Monday.

"We pushed deeper into the Old City and took control of new areas in the Faruq neighbourhood," he said.

The various Iraqi forces pushing into the Old City made modest gains, as ISIS fighters rained mortar fire on their positions and offered stiff resistance.

"Penetrating was very difficult. Today the fighting is face to face," Saadi said.

A US-led international coalition is providing air and ground support to the campaign.

Armoured vehicles were heading toward the front line north of the Old City, and shelling and gunfire could be heard.

The push into Mosul's historic heart on the west bank of the Tigris River marks the culmination of a campaign launched in October by Iraqi forces to retake ISIS's last major urban stronghold in the country.

The loss of Mosul would mark the effective end of the Iraqi portion of the cross-border "caliphate" that ISIS declared in summer 2014 after seizing swathes of Iraq and Syria.