Pentagon spokesman Colonel Steven Warren said his apparent death was significant because Emwazi was an IS “celebrity” and the world was a better place without him. He said intelligence gave the Pentagon “great confidence” he had been killed.
Emwazi was targeted by US forces in Raqqa and the Pentagon is using intelligence to verify that the extremist, who has appeared in videos showing western hostages being beheaded, is dead.
David Cameron said it had not yet been confirmed that “barbaric murderer” Emwazi was dead, but he added: “This was an act of self defence. It was the right thing to do.”
Labour leader Jeremy Corbyn disagreed, saying that while Emwazi had carried out “brutal and callous crimes… it would have been far better for us all if he had been held to account in a court of law”.
Emwazi appeared in videos showing the murders of British hostages Alan Henning and David Haines, American journalist Steven Sotloff, aid worker Abdul-Rahman Kassig and Japanese journalists Kenji Goto and Haruna Yukawa shortly before they were killed.
A US official told the Associated Press a drone had been used to carry out the attack on a vehicle in Raqqa which was believed to be carrying Emwazi.
The London-based Syrian Observatory for Human Rights said a leading British member of Islamic State and three other foreign militants had been killed in Raqqa, Islamic State’s de facto capital.
Director Rami Abdulrahman said: “All the sources there are saying that the body of an important British jihadi is lying in the hospital of Raqqa. All the sources are saying it is of Jihadi John but I cannot confirm it personally.”
Mr Haines, an aid worker from Scotland, was killed in September last year, having been held captive for 18 months. Mr Henning, a cab driver turned aid worker from Salford, was kidnapped in 2013 and held hostage for 10 months before being murdered.
Emwazi appeared in the videos dressed in black with only his eves visible, and spoke with a British accent while wielding a knife.
It was not until February this year that the jihadi was revealed to be Kuwaiti-born Emwazi, who had lived in the UK since the age of six before moving to Syria.