Iraqi forces in Mosul have freed an 11-year-old Yazidi girl who was kidnapped and sold as a slave by the "Islamic State of Iraq and the Levant" (ISIL) in 2014, the federal police said Friday (April 21st).

The girl was taken by the extremists from the village of Kosho, south of the Yazidi hub of Sinjar in northern Iraq, together with her mother and sisters, AFP reported.

She was freed during an operation by the security forces on Thursday in the west Mosul neighbourhood of al-Tanak, federal police chief Lt. Gen. Raed Shaker Jawdat said in a statement.

The Counter-Terrorism Service (CTS) has been operating in the area and secured more than half of the neighbourhood on Thursday.

"They who kidnap these children are monsters," Ma. Gen. Jaafar al-Baatat, Jawdat's top aide, said in a statement which was released with a video showing the girl at a police base south of Mosul.

Vian Dakhil, a prominent Yazidi lawmaker who helped bring her minority's plight to the world's attention when ISIL extremists swept through the region in 2014, said the girl's release had been carefully planned.

"When ISIL took her village on August 15th, 2014, she was eight years old and she was kidnapped with her mother and her sisters," she told AFP. "She was initially taken to Tal Afar and was sold on to Mosul."

On the police video, the girl stands silently, wearing a light green head scarf as officers try to reassure her.

"She has two sisters who were sold and sent to al-Raqa," said Dakhil. "They are still there."