IS executor 'Jihadi John' identified

The masked Islamic State (IS) militant known as "Jihadi John," who has appeared in several execution videos, has been identified as Briton Mohammed Emwazi of London, according to people familiar with the matter.

Emwazi, a Kuwaiti-born Briton in his mid-20s from west London, was previously known to British security services, the Washington Post reported Thursday.

"I have no doubt that Emwazi is Jihadi John," said one of his close friends who identified him in an interview with The Washington Post. "He was like a brother to me, I am sure it is him."

They chose not to disclose his name earlier for operational reasons.

Emwazi first appeared in a video last August last year, when he apparently killed American journalist James Foley.

He was later thought to have been pictured in the videos of the beheadings of US journalist Steven Sotloff, British aid worker David Haines, British taxi driver-turned-aid worker Alan Henning, and American aid worker Abdul-Rahman Kassig, also known as Peter.

In each of the videos, the militant appeared dressed in a black robe with a black balaclava covering all but his eyes and tip of his nose.

Speaking with a British accent, he taunted Western powers before holding his knife to the hostages' necks, appearing to start cutting before the film stopped. The victims' decapitated bodies were then shown.

Earlier this month, the militant featured in a video in which the Japanese journalist Kenji Goto appeared to be beheaded.

Hostages released by IS said he was one of three British terrorists guarding Westerners abducted by the group in Syria. They were known collectively as "The Beatles".