UN fears that up to a million people may still be trapped inside Mosul
Elite Iraqi troops have retaken a town about 12 miles from Mosul as Islamic State fighters inside the city said they would battle to the death.
France's President has said that the assault has already forced some Islamic State fighters to flee Iraq's second largest city, and they must not be allowed to escape.
Bartella fell to Iraq's forces after a day of fierce fighting, two years after it was seized by the militant group.
Dozens of black Humvee armoured vehicles were seen driving along the road to the town as helicopters flew overhead.
As they drove towards Bartella, a former Christian settlement, militants deployed nine suicide car bombs to attack the column.
One successfully hit an Iraqi vehicle but the others were destroyed before they reached their targets, according to an Iraqi officer.
Meanwhile, a video emerged on Wednesday apparently showing a group of militants south of Mosul, vowing to fight on until death to protect the honour of Muslims.
Another front in the battle for Mosul was opened to the north by troops from the Kurdish Peshmerga.
Soldiers shot down an IS drone that appeared overhead, similar to one that had killed two Kurdish troops a week before.
A suicide truck attack on Peshmerga troops in Telkif by Islamic State was filmed by a Kurdish television channel, embedded with Iraqi Kurdish forces.
Members of Iraq's elite counterterrorism forces pose for a photo as they advance towards the city of Mosul on Thursday | Photo: PA Images
Earlier, Prime Minister Haider al-Abadi had told an international meeting in Paris that the offensive was "advancing faster than expected".
France's Francois Hollande told the meeting that jihadists were already leaving for Raqqa, their stronghold in neighbouring Syria.
He told those at the meeting: "We can't afford mistakes in the pursuit of the terrorists who are already leaving Mosul for Raqqa. We cannot allow those who were in Mosul to evaporate."
The assault on Bartella was led by troops from Iraq's US-trained Counter Terrorism Service (CTS).
CTS commander Taleb Sheghati al-Kenani told reporters in the town: "Its residents, its churches and all of its infrastructure are now under the control of CTS."
The UN fears that up to a million people may still be trapped inside Mosul and could be forced to flee, sparking a humanitarian disaster.
The troops working to liberate the city have so far come across hundreds of civilians but it has been reported that a few thousand had left Mosul to cross into Syria.
Around 500 are now at a refugee camp and the others are on the border.
Further clashes took place between the Peshmerga and Islamic State at the Mosul Dam, about 30km north of the city.