Women in Mosul can venture out of their homes only when accompanied by a male relative Ammar Awad/Reuters

Women who Islamic State (Isis) deem to be improperly dressed in its stronghold in Mosul, Iraq, are being punished with a new instrument called the "Biter" or "Clipper". Those who have seen the torture device said it operates like an animal trap or metal jaw with teeth.

The revelation was made by a witness identified only as Fatima, who was forced to flee the city in January after her children faced certain starvation, besides rising IS (Daesh) brutality. Outside their homes, women in Mosul are expected to wear loose trousers, socks and gloves, and a veil, and must be accompanied by a male relative.

"The Biter has become a nightmare for us," Fatima told The Independent. "My sister was punished so harshly last month because she had forgotten her gloves. The bruises and scars are still visible on her arm," she added. Fatima said her sister told her that "the biting punishment is more painful than labour pains."

A man named Ghanem, 25, who now lives somewhere in north-east Syria, said brutality towards women has increased. He said IS uses the "Biter" to punish women who they think are showing "too much skin."

People who have managed to flee Mosul have said living conditions in the city have deteriorated drastically since it was captured by IS in 2014. "For me, I could stand the bad treatment and lack of food, but when my toddler of 11 months began to starve it became impossible to stay," Fatima said.

IS has a strict 'no-leave' policy in places such as Mosul, but corruption within the terror group has allowed many people to flee the city. Fleeing Mosul for Syria was dangerous at first, but Ghanem said a smuggler reassured him. "Don't worry. Money makes everything possible and [IS] will take their share," the smuggler reportedly told Ghanem.

Smugglers charge between $400 to $500 (£290 to £360) to secretly transport a person to safety from Mosul. However, some of the money from this smuggling operation, it is suspected, may be going back to IS, which is in desperate need for cash. In recent weeks US air strikes have targeted the terror group's cash storage facilities and oilfields under its control.