French Interior Minister Bernard Cazeneuve said on Monday there was a "strong possibility" that one of several unmasked "Islamic State" (IS) jihadists seen in a video purporting to show the execution of a US aid worker American Abdul-Rahman Kassig (pictured above) and at least 18 Syrian soldiers was a 22-year-old French citizen.

"This analysis [by French intelligence services] suggests with a very high probability that a French citizen could have directly participated in carrying out these abject acts," said Cazeneuve, adding that the man in question had left to go to Syria in August 2013.

'Pure evil'

Kassig's parents Ed and Paula Kassig from the US city of Indianapolis released a statement on Sunday following reports that their son, who took up the first name Abdul-Rahman after converting to Islam following his October 2013 capture, had become the latest foreign hostage to be murdered by IS.

Kassig had been delivering aid supplies in eastern Syria when he was taken hostage.

In a statement released on Monday, US President Barack Obama described the actions of the terrorist group as "pure evil."

"Today we offer our prayers and condolences to the parents and family of Abdul-Rahman Kassig, also known to us as Peter," he added, while praising him for his humanitarian work.

ksb/mz (AFP, Reuters)