Berlin: Germany on Sunday condemned the execution of British aid worker David Haines by an Islamic State militant as a "heinous act of barbaric violence".
Expressing her horror to British Prime Minister David Cameron, German Chancellor Angela Merkel added that "the unjustifiable act by terrorists must be punished", according to a statement from her office.
Separately the German foreign ministry issued a statement saying: "With the publication of the images of this murder, another taboo has been broken in an unacceptable fashion.
"Where Islamic State reigns, one kills, rapes or sets on fire. The international community should resolutely fight that which is a threat to Iraq, the surrounding region and also to us."