Windows rattle to the violent percussion of mortars and rockets.

Iraqi forces are advancing again, pushing further into western Mosul.

With Islamic State positions under fire the infantry soon rolls into action.

Battle for Mosul enters most dangerous phase

We join the Scorpion Unit of Iraq's Rapid Reaction Forces, which has been leading the offensive.

Like many of Iraq's fighting forces taking part in this campaign, they are on a personal mission of revenge and redemption.


In the summer of 2014, IS fighters overran military bases, stealing equipment and killing hundreds of soldiers.

Image: Iraqi troops are on a personal mission of revenge and redemption

The unit's work is nerve-wracking and it is now entering new and dangerous territory.

On the northern edge of Mosul airport, columns of armoured vehicles are led by tanks past the runway. Helicopter gunships open fire, strafing IS positions.

Beyond the airport we see the first of western Mosul's neighbourhoods. Relentless sniper fire targets Iraqi forces.

A mortar team is deployed along the perimeter of a building containing IS fighters and they begin firing.

Image: An Iraqi soldier holds a captured IS flag aloft

Moments later a counterattack is launched and everyone is sent running for cover.

Iraq's forces may be weary after years of war but they are determined to dislodge IS from their towns and cities.

Liberating Mosul is their final, and most difficult, challenge.

For the civilian population these are terrifying times.

We see families cower in their homes while others tentatively venture out, offering support to the oncoming forces.

Image: A Scorpion Unit soldier fires a rocket launcher at IS fighters

To avoid any risk of being mistaken for suicide bombers the men remove their trousers and jackets before approaching.

Those suspected of being IS fighters are handcuffed and questioned by the federal police. Some of them are taken away for further interrogation.

It could take the Iraqi army months to clear these streets but few people doubt they will succeed.

After the divisions sown by Islamic State's poisonous ideology, bringing the country together again will be far harder to achieve.