“Praise be to God, we managed to liberate (the city) and proved the others were wrong, the people of Mosul supported and stood with our security forces against terrorism,” Mr Abadi told reporters at a news conference in Baghdad on Tuesday night.
Instructions have already been issued on rebuilding the city - devastated by Isis improvised explosive devices (IEDs) and coalition bombing - and improving the security situation, he added.
Mr Abadi’s remarks came three years to the day since Isis’ leader Abu Bakr al-Baghdadi made his only public appearance at Mosul’s al-Nuri mosque, leading Friday prayers and urging Muslims worldwide to join the just-declared Islamic state.
Iraqi troops seized the ruins of the mosque last week, using the symbolic victory to declare that the Iraqi half of the caliphate had been toppled.
Isis blew up the 12th century building on 26 June after it became apparent the US-backed Iraqi forces had begun a push in its direction.
Its black flag had flown from the al-Hadba (Hunchback) minaret since June 2014, when the extremists managed to capture one third of Iraq after sweeping across the border from Syria.
Now Isis clings on to just a handful of neighbourhoods in the winding streets of Mosul’s Old City, although Iraqi forces have forced them into an area less than one kilometre squared on the West bank of the Tigris River.
Civilians continue to flee from Isis territory in large numbers - many weak and emaciated after weeks of coping with little food, water and medicine in the 50 degree heat.
“None of the previous battles were like this,” Major Faris Aboud, working at a small field hospital just outside the Old City, told the AP.
“In a single day we received 300 wounded,” the father of three continued. “For me, seeing the wounded children is the hardest, we see children who have lost their entire families under the rubble, they have no one now.”
Across the border in Syria, Isis’ grip is also loosening on its last city of Raqqa as US-backed Arab and Kurdish militias advance through the city’s neighbourhoods.
The security situation in the region is expected to remain volatile, however.
Analysts expect the organisation to morph into a full-blown insurgency across the two countries, mounting sleeper cell assaults and suicide bombings in areas declared liberated from its rule to provoke continued unrest.
A man who asked to only be referred to as Abu Abid, for fear for his family's safety, was waiting to get a spot on a truck after fleeing the Old City when he was approached by an AP reporter.
“That place, it was absolute death,” he said. “We will never be the same. Once the fear has been planted in your heart, you can't get rid of it.
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