MOSUL (Reuters) - One by one, hundreds of Mosul residents raised their shirts to prove they did not have suicide bombs strapped to their bodies, closely watched by Iraqi special forces fearful of the threat posed by Islamic State, even in areas they now control.
The men then handed over their identification cards so their names could be checked against a database of wanted Islamic State members, part of the painstaking process of clearing jihadists from each neighborhood of their Mosul stronghold.
Every time Iraqi forces capture a section of Mosul in their offensive against Islamic State, it can take up to a week to ensure it is clear of militants.
Some hide in the network of tunnels they have constructed, while others mix with thousands of displaced people or stay behind to form sleeper cells in the crowded neighborhoods of Mosul, a city of more than one million people.
Iraqi security officials say they have seized a large area of eastern Mosul in the biggest ground operation in the country since the U.S.-led invasion that toppled Saddam Hussein in 2003.
Iraqi leaders hope the Mosul campaign will bring stability after years of sectarian bloodshed followed by the arrival of Islamic State, an ultra-hardline Sunni group, in 2014.
While the Iraqis seem confident of victory, the security clamp-down in the Shuqaq al-Khadra'a district of Mosul suggests Islamic State still poses a threat even as it loses territory.
Iraqi special forces were on patrol when their intelligence division heard from local people that Islamic State militants were still in the area.
Special forces and intelligence officials ordered residents to gather at a square with their identification documents.
"Lift up your shirt now," one officer yelled at a man, acutely aware that suicide bombers are one of Islamic State's most effective weapons.
The residents, many with beards of the size required by Islamic State, sat in rows as their names were called. From time to time, a mortar bomb exploded nearby or shooting rang out.
Sitting at computers, special forces officers compared the names on identification cards to a long list of wanted men.
"There are about 39,000 wanted men in Iraq," said Mohamed Ali, a National Security officer. About 80 percent, he added, are "terrorists", the term Iraqi officials use to describe Islamic State and other militants.
As identification cards were handed over, senior intelligence official Hussein Za'alan lectured the men sitting on the ground about the "evils" of Islamic State, hoping they would provide information on the militants.
"They brought foreign fighters, criminals to this country," he said. "They just take women, impregnate them."
Another officer also sought to win the trust of the residents of predominantly Sunni Mosul, where Islamic State won support initially because of widespread discontent with the Shi'ite-led government in Baghdad.
"We need your cooperation. Don't be scared. Remove fear from your hearts. Daesh is finished," he said, using a derogatory Arabic acronym to describe Islamic State.
"Look what they do. They turn your young children into suicide bombers."
The officer didn't have to look far to see how easy it is for Islamic State to recruit young Iraqis.
Omar Abdullah, 51, one of the men being processed, sat beside his 16-year-old son, Ibrahim. The teenager attended Islamic State indoctrination lectures on religion for 10 days before Abdullah managed to persuade him to leave the group.
But he was not so lucky with another son, who is an Islamic State fighter in the nearby city of Tal Afar.
"He wanted to get married but he didn't have the money because times are tough," said Abdullah. "Daesh brainwashed him, gave him money and promised him virgins in heaven. I lost my son."
An elderly man who did not immediately admit his son had joined Islamic State was chastised in front of the group. "You lied to me. You are Islamic State," a special forces officer shouted.
As intelligence officials lectured the men, some residents identified one of those in the square as an Islamic State member.
With a hood put over his head, he was handcuffed and questioned. "Talk, talk," yelled an interrogator.
"We are investigating. He could be Daesh, or the people that ratted him out may just have something against him and are trying to get him in trouble," he told Reuters.
Four more suspected jihadists sat nervously in a room, awaiting their turn.
(For a graphic on areas of control in Mosul click here)
Editing by Giles Elgood