Iraqi forces have entered the city of Mosul for the first time in two years as they attempt to recapture one of Isis’s last remaining strongholds.
A coalition of forces - including the Iraqi army and special forces, Kurdish Peshmerga and Shia militias - and backed by US-led air strikes, has been fighting to retake the area for the past two weeks.
Recapturing Mosul, Iraq’s second biggest city, would mark a significant shift in the fight against Isis.
The city, which still has a population of 1.5 million, was where Isis leader Abu Bakr al-Baghdadi first announced the creation of an Islamic caliphate in 2014 and has been strategically important to the group since then.
Iraqi troops reached Mosul on Monday but have been held up by Isis snipers, improvised explosive devices (IEDs) and suicide attacks.
As the fight to recapture Mosul got under way, residents reported heavy explosions shaking the city as militants fired rockets at the advancing Iraqi soldiers.
One said: “We heard the sounds of rockets firing one after the other and saw them flashing through the air. The house was shaking and we were terrified, not knowing what was taking place."
Isis fighters were reported to be roaming Mosul’s streets pledging to fight until the death. There are believed to be up to 7,500 militants in and around the city.
Brett McGurk, President Obama’s anti-Isis envoy, tweeted: “Milestone: Iraqi forces enter eastern neighborhoods of #Mosul this morning. New advances on all axes. Ways to go, but ahead of schedule.”
After entering the city, Iraqi forces discovered a huge network of tunnels dug to allow Isis fighters to escape to nearby villages.
However, the militants are mostly surrounded after Shia militia groups captured territory to the west on Mosul, cutting off a key supply line and possible escape route.
The battle for Mosul led Baghdadi to release his first audio message since last December to encourage his followers.
In the recording, released on the internet by Isis supporters, he said: “Know that the value of staying on your land with honour is a thousand times better than the price of retreating with shame."
Baghdadi called on Isis militants to “"turn the nights of the unbelievers into days, to wreak havoc in their land and make their blood flow as rivers".
The self-declared caliph also urged followers to “unleash the fire of their anger” on Turkey, which is fighting against Isis troops in Syria, and launch “attack after attack” on Saudi Arabia, which is also part of the coalition taking on Isis.
In an apparent attempt to raise militants’ morale, the speech was reportedly being broadcast from speakers attached to Isis vehicles patrolling the streets of Mosul.
Baghdadi, an Iraqi whose real name is Ibrahim al-Samarrai, was believed to be hiding in Mosul in recent days. His current location is unknown, with British Foreign Secretary Boris Johnson saying intelligence suggested he had “vacated the scene”.
Isis fighters have taken control of large swathes of northern Iraq and eastern Syria since the summer of 2014.
However, they have been forced to retreat by the counter-offensive launched by 100,000 forces consisting of the Iraqi army and other groups. Only Iraqi army forces are entering Mosul, sources said, in an attempt to minimise sectarian differences.
The offensive has seen Iraqi forces recapture towns and villages across northern Iraq.
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