Updated: 09/02/18 : 07:09:36
Two British men believed to be members of a notorious Islamic State group (IS) cell have been seized by Syrian Kurdish fighters, US officials say.
Alexanda Kotey, 34, and El Shafee Elsheikh, 29, were the last two members of the cell to remain at large.
The four, all from London, were nicknamed "the Beatles" because of their British accents.
US officials said the "execution cell" had beheaded at least 27 Western hostages and tortured many more.
The latest arrests were confirmed by US officials.
Officials quoted by US media said the two men had been captured by members of the US-backed Syrian Democratic Forces (SDF), who are targeting remnants of IS.
The UK Foreign Office, meanwhile, said it did not comment on individual cases or investigations.
Their capture was first reported by the New York Times, who noted that American officials had wanted to keep the news secret.
The aim was "to allow analysts more time to pursue the intelligence leads developed from their detention and prepare raids against unsuspecting Islamic State targets", the newspaper said.
The Syrian fighters who apprehended them told US officials in mid-January that the two may have been captured, and the men's identities were later confirmed using fingerprints and other biometric data.