The Pentagon says it is “reasonably certain” that a US drone strike in Syria has killed the Islamic State militant known as “Jihadi John”.
Col Steve Warren said Thursday’s attack in Raqqa had hit the intended target, but it would take time to “formally declare that we have had success”.
Mohammed Emwazi, a Kuwaiti-born British militant, appeared in videos of the beheadings of Western hostages.
UK PM David Cameron said targeting Emwazi was “the right thing to do”.
It is believed there was one other person in the vehicle targeted in the strike.
Col Warren said such “routine” attacks had killed on average “one mid- to upper-level IS leader every two days” since May.
However, the death of Emwazi would be a “significant blow” to IS, even though he had not been an “operational or major figure” for IS.
Separately, Turkish officials in Istanbul say they have detained a British man, believed to be Aine Lesley Davis, an alleged accomplice to “Jihadi John”. Aine Davis is believed to have been guarding foreign prisoners in Syria.
‘Strike at IS heart’
Speaking outside Downing Street, Mr Cameron said it was not certain whether the strike was successful, but the UK had been working with the US “literally around the clock” to track Emwazi down.
He said any successful attack would have been “a strike at the heart” of Islamic State (IS), and would demonstrate to those who would harm Britain that “we have a long reach, we have unwavering determination and we never forget about our citizens”.
Three drones – one British and two American – were involved in the strike. One of the American drones hit the militants’ car.
Emwazi appeared in beheading videos of victims including British aid worker David Haines and taxi driver Alan Henning.
Mr Haines’s daughter Bethany said she felt an “instant sense of relief” upon hearing reports of Emwazi’s possible death, “knowing he wouldn’t appear in anymore horrific videos.”
“He was only a pawn in Isis’s stupid game, but knowing it’s over, that he’s finally dead, still hasn’t sunk in,” she said in a statement.