IS leader behind 'Jihadi John' beheading of US aid worker Peter Kassig killed in drone strike

Abu al-Umarayan is believed to be behind in the brutal beheading of Peter Kassig in November 2014.

Peter Kassig standing in front of a truck filled with supplies for Syrian refugees. Source: Supplied

The US-led coalition against the Islamic State group say they have killed a senior jihadist involved in the executions of an American aid worker and other Western hostages.

Abu al-Umarayn was involved in the November 2014 beheading of Peter Kassig, a former US Army Ranger who was doing volunteer humanitarian work when he was captured in 2013.

"He was killed and more information will be available after a full assessment," Sean Ryan, spokesman for the US-led coalition, said in a statement issued after the Sunday strikes.

Peter Kassig standing in front of a truck filled with supplies for Syrian refugees. Source: Supplied

"Al Umarayn had given indications of posing an imminent threat to coalition forces and he was involved in the killing of American citizen and former US Army Ranger, Peter Kassig," he said.

Ryan said the jihadist had also been involved in the execution of several other prisoners.

The American was beheaded on camera, in a video released by the so-called Islamic State. Source: Supplied

It is the first time the coalition, which has been hunting down IS fighters in Iraq and Syria since 2014, has announced the killing of a jihadist leader linked to Kassig's death.

At the time of the execution, IS released a video showing Kassig's severed head but did not publish footage of the decapitation, as it had done for other hostages.

IS executioner Mohammed Emwazi - aka "Jihadi John" was believed responsible for the killing, along with the deaths of other Western hostages.

The Britain-raised IS fighter was killed by a drone strike in 2015.

Ed and Paula Kassig, parents of Peter Kassig, speak during a news conference. Source: AP