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A British man believed to be part of a group of Islamic State militants led by "Jihadi John" has had sanctions imposed against him by the US.

Alexanda Kotey, 33, from west London, has had his assets frozen by the US State Department.

He has been identified as one of four men known as "The Beatles", who reportedly imprisoned and beheaded hostages for so-called Islamic State.

Kotey is also said to have recruited UK nationals to the terror group.

The US State department said he was one of four members of a terrorist group responsible for beheading about 24 hostages.

Kotey acted as a guard and is likely to have taken part in its executions and torture methods, it added.

The terrorist group was led by Mohammed Emwazi, known as Jihadi John, who was killed in a US drone strike in 2015.

He appeared in beheading videos of victims including British aid worker David Haines and taxi driver Alan Henning.

Image caption "Jihadi John" - whose real name was Mohammed Emwazi - regularly featured in IS propaganda

The two other members of the group are said to be Aine Davis, who was arrested in Turkey in 2015 , and mechanic El Shafee Elsheikh, a former child refugee - both from west London.

Identifying Kotey as a "specially designated global terrorist", the US State Department said: "As a guard for the cell, Kotey likely engaged in the group's executions and exceptionally cruel torture methods, including electronic shock and waterboarding.

"Kotey has also acted as an Isil recruiter and is responsible for recruiting several UK nationals to join the terrorist organisation."

The US has banned its citizens from having any dealings with him and has put a freeze on any property or interests he has within the country.

An investigation by the Washington Post and Buzzfeed, which identified Kotey as being part of the terrorist group, said he converted to Islam in his mid-20s.

He reportedly became involved with a network of extremists known as the "London Boys" who advocated violence and have been linked to terrorist attacks and plots in the United Kingdom.