A BRITISH terrorist who held a Winchester man hostage has been killed in an airstrike by the US military according to reports.

Sources close to the Islamic State (IS) stronghold of Raqqa in Syria said the British terrorist Mohammed Emwazi, known as Jihadi John, was targeted by a drone during an operation last night.

Prime Minister David Cameron has today welcomed the news as "a strike at the heart" of terror group Islamic State. However, he said it had not been confirmed that Emwazi was dead.

He said Britain had been working "hand in glove" round the clock with its closest ally the US to track down and target the militant.

In a statement outside 10 Downing Street, the Prime Minister said that Emwazi had remained a threat to innocent people, including in the UK. He added: "This was an act of self defence. It was the right thing to do."

Emwazi is believed to be responsible for the deaths of several IS hostages including 47-year-old Salford taxi driver Alan Henning and David Haines, an aid worker from Scotland.

But the future of Winchester photojournalist John Cantlie, who has been held hostage by the terror group for more than three years, is unclear.

It comes after his father Paul Cantlie, 80 of Union Lane in Droxford, died last year after complications following pneumonia.

The 44-year-old has appeared in several IS propaganda videos since his capture.

Mr Cantlie, who has worked for The Sunday Telegraph and The Sunday Times, has mostly appeared delivering messages apparently under duress from behind a desk and wearing an orange jumpsuit but in more recent footage, released last October, he is seen walking through the war-torn streets which he says are in Syria.

In those videos he told how prisoners have been waterboarded for trying to escape and read emails allegedly exchanged between IS and the families of American captives who complained about the US government's refusal to negotiate their loved ones' release.

Emwazi came to notoriety in a video in August 2014 which showed the beheading of US journalist James Foley.

He also appeared in videos showing the killings of Mr Henning and Mr Haines, American journalist Steven Sotloff, aid worker Abdul-Rahman Kassig and Japanese journalists Kenji Goto and Haruna Yukawa shortly before they were killed.

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

It emerged that Emwazi had been known to British intelligence services, but managed to travel to Syria in 2013.

Last night's operation is being investigated by the Intelligence and Security Committee (ISC) which oversees the work of MI5, MI6 and GCHQ, after concerns were raised about its legal basis.

Rami Abdel Rahman, director of the Syrian Observatory for Human Rights, said the drone strike "killed the British leader of Isis last night".

He said sources in Raqqa confirmed the death, but that they were uncertain of the man's identity at present.

Pentagon press secretary Peter Cook confirmed US forces conducted an air strike in Raqqa last night "targeting Mohamed Emwazi."

It comes as Kurdish fighters, backed by US-led air strikes, took the Iraqi town of Sinjar back from IS control.   

Witnesses said fighters raised a Kurdish flag and fired celebratory gunfire in the town centre after freeing it from the terrorists' grip more than a year after it was seized.

Kurdish fighters have also reportedly taken a main road near Sinjar which helps connect Mosul and Raqqa - key areas for IS.