Iraqi prisoners who were rescued from ISIS last week have spoken of their treatment at the hands of the militants.

A video, released by the Kurdistan Region Security Council, shows the captives talking about their time in jail.

"Torture techniques included electric shocks, plastic bags over the head, beatings with a cable and a piece of wood - torture that no human may have ever witnessed," said Saad Khelef Ali Feraj, a police officer from Hawija.

"My brother, who was an officer, was taken and beheaded. They gave me only his head, without his body. I buried his head."

This latest film follows another video apparently showing footage of the raid between US and Kurdish forces which led to the release of the 69 prisoners. The day before the raid, the jihadis told the captives they were to be executed and gave them the night to write letters to the loved ones.

"It was 1.30am, I was writing a letter to give to any prisoner to give to my family," said Saad. "At exactly 2am Counter Terrorism forces of Kurdistan Region and US Special Forces arrived and rescued us from ISIS."

"I am sending this message to my family from here to tell them I'm in the Kurdistan Region. God willing, I will return to my family as soon as possible. I can't describe how I feel. I was dead."

Another victim, Akram Hussen Mohammed Zahir, described how he was tortured nearly everyday.

"They took you before a judge who ordered another investigation (torture)," he explained.

"Same questions asked every day and beatings repeated. Look at my foot to see how I was tortured. They also broke my teeth.

"When they (ISIS) would come to take us for interrogation, they'd cover our eyes and tie us with handcuffs,' he said.

"First thing they did was pour water over us, then they'd use electric shocks. We had to say something. Torture would continue unless there was a confession.

"A confession, however, meant execution. A bag would be placed over the head until loss of consciousness. Electric shocks were then used on the neck and nose. After regaining consciousness the same questions would be asked. Not answering would lead to the same torture."

Other prisoners told of how they had not seen daylight in over five months of captivity.

The raid was among the most significant carried out against ISIS. Six jihadis are said to have been arrested and more than 20 killed.

One US soldier, Special Forces Master Sergeant Joshua Wheeler, was also killed in the raid. He is the first American casualty to have died while fighting ISIS.