An airstrike targeting the British IS militant Mohammed Emwazi, known as Jihadi John, has been carried out in Syria by US forces.

The extremist appeared in a number of beheading videos, including those in which UK hostages Alan Henning and David Haines were killed.

Pentagon press secretary Peter Cook said it was not clear whether Emwazi had been killed in the strike in Raqqa.

He added that the Pentagon is currently assessing the results of the military action.

Emwazi was first seen, with his face covered, in a video in August 2014 which showed the beheading of US journalist James Foley.

He also appeared in videos showing the killings of American journalist Steven Sotloff, and worker Abdul-Rahman Kassig and Japanese journalist Kenji Goto.

It was not until February this year that the jihadist was unmasked as Kuwaiti-born Emwazi, who lived in the UK since the age of six.

A US official told the Associated Press a drone had been used to carry out the attack on a vehicle which was believed to be carrying Emwazi.

British aid worker David Haines was executed in September last year, having been held captive for 18 months.

A video released a month later showed 47-year-old Salford taxi driver Alan Henning appearing to be beheaded.

His daughter Lucy said she found out he had been killed when she saw an image posted on social media site Instagram.

Emwazi is believed to have travelled to Syria in 2013.

On moving to the UK as a child his family settled in the Mozart Estate in west London - one of the capital's most notorious estates which has been blighted by gangs and violence.

He later attended the University of Westminster and graduated with a degree in information systems with business management.

A Downing Street spokeswoman said: " We are aware of the US statement about the air strike targeting Mohamed Emwazi. Like them, we are not commenting further at this stage."

Man linked to Jihadi John detained in Turkey

Authorities in Turkey have detained a man they suspect is Jihadi John.

An official said the man, who they strongly believe to be Aine Lesley Davis, was detained in Istanbul, without providing further details.

Authorities were still investigating to confirm his identity "one hundred per cent," the official said.