Islamic State's Egypt-affiliate, Sinai Province, released a still photo of the beheaded body of a Croatian hostage the group had threatened to kill last week, the SITE monitoring service said on Wednesday.
Reuters could not independently verify the authenticity of the photo, which included a caption that said "killing of the Croatian hostage, due to his country's participation in the war against Islamic State, after the deadline expired ... ".
SITE said the photo was distributed on Twitter on August 12. A spokesperson from the Egyptian interior ministry's press office said: "We have seen this news online but are currently making our own checks. If we confirm that it is indeed true, we will inform the media through a statement."
Last week, an online video purportedly from Sinai Province showed a man who identified himself as Tomislav Salopek who said the group would kill him in 48 hours if Muslim women in Egyptian jails were not freed.
Ardiseis Egypt, a unit of French firm CGG, which specialises in oil and gas geology, said last week one of its staff had been kidnapped on July 22 while travelling to Cairo.