Inside the Syria prison where Welsh IS soldier is being kept

Pictures from within a Kurdish detention centre for suspected Islamic State members show the squalid conditions that alleged fighters now languish in.

There are 5,000 inmates inside the jail, where many of them appear malnourished and packed inside the prison head to toe.

Looking at the grim faces of the men, you would never know that some of them where heads of an organisation that once controlled vast swathes of Iraq and Syria.

Accused of horrific crimes like beheading, rape and genocide, the caliphate has been severely wounded by a combined effort of international forces including the Kurds.

You can see pictures from inside the prison here:

The men are so skinny you can see their bones (AFP via Getty Images)

Some of the fighters are incredibly young (AFP via Getty Images)

One of the inmates gestures at the camera (AFP via Getty Images)

Some of the cells are so crowded there is no floor space at all (AFP via Getty Images)

There are concerns that if they return to their home countries they could be a threat (AFP via Getty Images)

The pictures from AFP (Agence France-Presse) show men from all over the world including Syria, Iraq, France, Germany and Wales.

The pictures come just weeks after a Turkish offensive against Kurdish forces threw the area, and the security of the prisoners, into chaos.

Aseel Muthana, from Cardiff, is one of the men inside the prison. He worked in Cardiff selling ice cream before leaving his family and travelling to Syria in 2014 at the age of 17.

Aseel Muthana has been traced to a Syrian prison (Wales News Service)

He followed his brother, Nasser Muthana, and a friend, Reyaad Khan, who had joined the brutal extremist group months earlier. They became some of Britain's most high-profile Islamic State members.

Inside the prison, Muthana told ITV News he was lured into going to Syria by propaganda that claimed he would be helping Syria's poor by fighting on the side of Islamic State.

The father of two brothers who fled Cardiff to join Islamic State (IS) in Syria opens up about losing his sons

"Back then when I first came to Isis, you have to understand I came way before the caliphate was pronounced," he said.

"Before all of these beheading videos, before all of the burnings happened, before any of that stuff.

"We came when Isis propaganda and Isis media was all about helping the poor, helping the Syrian people.

"We stuck with the people you know from the UK and from Wales.... the Welsh guys... me and my brother and Reyaad [Khan]."

Kurdish sources say around 12,000 IS fighters including Syrians, Iraqis as well as foreigners from 54 countries are being held in Kurdish-run prisons in northern Syria (AFP via Getty Images)

At one point IS controlled vast swathes of Iraq and Syria (AFP via Getty Images)

Earlier this year, Aseel's father Ahmed told WalesOnline he  did not know if his sons were alive or dead .

He also said that Aseel had married a Somalian woman who had travelled from Glasgow.

Reyaad Khan was killed in a RAF drone strike over Syria in 2015. The current status of Aseel's brother Nasser is unclear although there have been some reports he died in 2016.