Image copyright AP Image caption FBI Director James Comey says he will not share the name of the militant

The FBI has identified the militant in the videos depicting the killings of two US journalists and a British aid worker, the agency's director has said.

But James Comey says the FBI will not yet release the name of Islamic State fighter, so-called Jihadi John, who seemed to speak with a British accent.

UK Foreign Minister Philip Hammond told CNN this week they were "getting warm" on the identity of the masked man.

Mr Comey did not say whether the man identified carried out the killings.

He said the FBI was able to identify him with the help of international partners.

American journalists James Foley and Steven Sotloff, and British aid worker David Haines, have all been killed alongside a masked man dressed in black holding a knife, who speaks to the camera.

The life of another British citizen, Alan Henning, was threatened in the last video.