ISIS fighters jailed in Syria – including Brit Jihadi Jack – have been warned they now face execution without trial.
President Bashar al-Assad is setting up one-sided courts where terror suspects will be tried under hardline local laws.
In Syria, membership of ISIS is a hanging offence and Assad promises foreign fighters will not escape punishment.
Thousands of prisoners have already been secretly executed inside Saydnaya Prison, claims Amnesty International.
Thousands more are said to have died through torture and starvation inside the brutal jail near Damascus.
Assad made his comments in an interview with Paris Match when asked about a deal with a Kurdish-led force which would eventually bring the north of the country under government control.
The Syrian Democratic Forces – who defeated ISIS with the help of the US-led coalition – are now holding more than 10,000 militants.
Although most are Syrians and Iraqis those being kept inside the jails also include around 2,000 foreigners including so-called Jihadi Jack.
In October, the terror coward was spotted cowering on the floor of a Syrian hellhole prison in a TV news report seen by his desperate parents.
Footage emerged of Jack Letts – who once declared himself an “enemy of Britain” – looking gaunt as he curled up in a overcrowded cell.
It showed him in an orange jumpsuit alongside other inmates who had been captured by Kurdish militia.
Letts is believed to be behind bars in the city of Qamishli – where he has been held without charge or trial.
The 23-year-old left a plush middle class life to join ISIS in Syria, but was captured by Kurdish forces as the terrorist caliphate collapsed.
After being captured, he meekly pleaded to be allowed back to his Oxfordshire home saying he had “no intention of blowing up Britons.”
However, his chances of ever returning to Britain were dealt a hammerblow when the SDF turned to tough guy Assad for help after being abandoned by the US.
He said: “Every terrorist in the areas controlled by the Syrian state will be subject to Syrian law and Syrian law is clear concerning terrorism.
“We have courts specialised in terrorism and they will be prosecuted.” .
Most European countries are refusing to take back their citizens and a number of French ISIS prisoners have already received death sentences in trials in Iraq.
Letts was stripped of his UK citizenship in August by former Home Secretary Sajid Javid, according to reports.
His mother Sally Lane has long pleaded for him to be allowed to return and face trial in this country.
She said after seeing image of her son in prison: “It’s heart-rending to see your son like this and to feel so completely powerless.”
Jihadi Jack once described himself as an ‘enemy of Britain’
