David Cameron requested the addition of 18-year-old Muthana to a UN Sanctions list, alongside four other Brits known to have joined Islamic State militants.
Muthana, originally from Cardiff, fled to Syria when he was just 17 in 2014, and became well known for his age and for his apparent dedication to ISIS and Jihad. In an online interview with the BBC, he said: “I am willing to die but Allah knows the truth behind the words.”
He joins a collection of other British nationals on the sanctions list, including Omar Hussain, Aqsa Mahmood, Sally-Anne Jones and older brother Nasser Muthana seen below. Other Brits already on the list are radical cleric Abu Hamsa al-Masri and Mohammad al Ghabra who has links to al-Qaeda.
The list is compiled of some 231 individuals from 72 terrorist organisations, and was made with the intent of stopping them from travelling between countries. Aseel and his brother can be seen on the list below, the full copy is available here.
According to the BBC, police believe around 700 British nationals have travelled to Syria and Iraq to join ISIS, though half of them have since returned to the country.