Islamic State Beheads British Hostage Alan Henning

The Islamic State released a video Friday showing the execution of British hostage Alan Henning.

Henning has become the fourth western hostage killed by the Islamic State recently after the group executed U.S. journalists James Foley, Steven Sotloff and British aid worker David Haines.

In the video, Henning wearing an orange jumpsuit is seen kneeling in a desert. A masked militant holding a knife is shown standing next to Henning.

Henning then issues a statement referring to the British parliament's decision to join the airstrikes against the Islamic State.

"Because of our parliament's decision to attack the Islamic State, I, as a member of the British public, will now pay the price for that decision," Henning  says.

The masked militant then says that the killing is in response to Britain's decision to join the fight against the Islamic State in Iraq.

 "The blood of David Haines was on your hands, Cameron," the militant says in the video. "Alan Henning will also be slaughtered, but his blood is on the hands of the British Parliament," he said, reports Reuters.

At the end of the video, the militant introduces another hostage identified as Peter Edward Kassig, a former U.S. Army Ranger. The militant then threatens that Kassig could be their next victim.

The militant then warns Obama that the Islamic state would continue to kill the citizens of countries which were conducting airstrikes in Syria as the airstrikes have killed several Islamic State militants, reports the Associated Press.

Alan Henning, 47, was kidnapped in December in Syria after he crossed from Turkey as part of an aid convoy taking medical supplies to a hospital.

His wife Barbara Henning had issued a statement last month requesting the Islamic State to release him. Several Muslim leaders and Imams had also requested the Islamic State to release Henning.