The US-led coalition against the Islamic State group said Monday it 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 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.

"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.

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.