More than 100 Daesh members in the Kirkuk region have been jailed and another 250 are in prison awaiting trial, but sleeper cells still pose a threat with surprise attacks.
As Iraqi forces intensify their campaign against Daesh, police and intelligence services are searching for Daesh members still in liberated areas.
More than 100 men in the Kirkuk region have been jailed for 15 to 20 years and some sentenced to death for joining Daesh, according to police.
Another 250 are in prison, waiting for their day in court.
"Most of the Daesh fighters are Arabs, Saudis, and Syrians. The foreigners were very few. When I was still with Daesh, there was a total of 400 to 600 fighters," said one prisoner who joined Daesh in the town of Hawija.
"The fighters were filled with fear when the leaders were defeated and fled to Syria before the road was cut," he said.
In Kirkuk, Iraqi forces continue to track down Daesh.
"Thirty percent of Kirkuk province was controlled by Daesh, including one district and more than 500 villages. There were more than 2,000 Daesh fighters there," said Iraqi Brigadier General Serhet Mouhammed.
"The men who were trained by Daesh still pose a threat, and if they have a chance they could carry out a terrorist attack."
TRT World's Nicole Johnston has more on the battle against Daesh in the northern province.
Iraqi forces advance in battle for Mosul
Iraqi officers on Wednesday said their forces had found more than 20 Daesh missiles in a warehouse in western Mosul.
The discovery came after government troops seized a third bridge linking eastern Mosul with the Old City on the western side of the Tigris river.
The seizure of the Iron Bridge bolsters Prime Minister Haider al Abadi's assertion that the battle for Mosul is reaching its final stages.
Iraqi federal police on Wednesday said government forces battling Daesh for Mosul are advancing towards the mosque where the group's leader declared a so-called caliphate in 2014.
"Our troops are making a steady advance towards the Grand Mosque and we are now less than 800 metres from the mosque," a police spokesman said.
Civilians flee fighting
Amid the combat, a steady stream of refugees continues to leave western districts of Mosul, carrying suitcases, bottles of water and other possessions. Some push children and sick elderly relatives in handcarts and wheelbarrows.
As many as 600,000 civilians are caught with the terrorists inside Mosul, which Iraqi forces have effectively sealed off from the remaining territory that Daesh controls in Iraq and Syria.