Two weeks after Iraqi forces launched an operation to recapture Isis-held Fallujah, both the sides have been accused of human rights violations.

Hundreds of civilians were reportedly tortured while being held by Shia militias who advancing towards the Islamic State (Isis) stronghold in central Iraq. According to Yahya al-Muhamadi, an Anbar council member working with displaced civilians, five of those detained died while in the group's custody.

However, one of the militia forces called the Popular Mobilisation Forces (PMF), working along with the Iraqi forces to combat IS in the country, has denied allegations of detaining any civilians.

"We are not authorised to detain anyone, we are just helping to move displaced people," Hayder Mayahii, a PMF official, said, rejecting the claims as false and the product of media bias, according to AP reports.

However, al-Muhamadi said the PMF illegally detained 605 people. "They tortured many of them, five people died from the torture," he added.

Iraqi forces have recently retaken from IS areas nearby to Fallujah, like Saqlawiya in the north. Buses carrying families from these areas were transported to the east of Fallujah. Men and teenage boys from the recaptured territory are regularly detained by the Iraqi police for a legal screening process to prevent IS militants from escaping among the civilians, al-Muhamadi said.

The screening process takes three to five days, according to Iraqi security officials who are in charge of the registration process required to resettle civilians from a besieged area to a safer place. However, human rights group Amnesty International said such civilian detained are often held forever without any charges against them, with tens of thousands of them still estimated to be in the custody of Iraqi forces since December 2015.

Although The Iraqi government has encouraged civilians to flee, IS has threatened any resident attempting to escape from Fallujah with death.

Hana Hussein, 45, said she was separated from her three oldest sons before she was asked to board a bus. She and her daughters were registered on Monday (6 June) night on the east of Fallujah. "They said they are going to check their names in a database. No one told me for how long they would be held; honestly I don't know when I will see them again," she told AP.

An Iraqi officer on the site told the crowded bus with civilians not to worry. "Daesh will be finished in just one or two more days, god willing."

Civilians flee falluja
A member of the Iraqi security forces carries a child as he assists civilians, who had fled their homes due to clashes at Camp Tariq, south of Fallujah, on 4 June 2016REUTERS/Thaier Al-Sudani