The Foreign Secretary has condemned the apparent murder of a Croatian hostage held by so-called Islamic State's (IS) Egyptian affiliate.
Philip Hammond insisted Britain would stand by Croatia and Egypt as they oppose "this inhuman brand of terrorism" following the emergence of an online image purporting to show the beheading of Tomislav Salopek.
The 30-year-old oil and gas sector surveyor is the first foreign captive to be killed in this way in Egypt since the extremists set up a branch in the country.
His death follows the IS killings of foreign journalists and aid workers in Syria, including Britons David Haines and Alan Henning.
The Associated Press (AP) reported a still image, shared by IS sympathisers on social media, appeared to show the body of Mr Salopek wearing a beige jumpsuit.
A black flag used by IS and a knife were planted in the sand next to the married, father-of-two.
AP added the photo carried a caption in Arabic that said Mr Salopek was killed "for his country's participation in the war against the Islamic State", and after a deadline had passed for the Egyptian government to meet their demands.
The picture also contained an inset of two Egyptian newspaper reports, with one headline declaring Croatia's support of Egypt in its war against terrorism and extremism and another saying Croatia reiterated its support for the Kurdistan region.
Croatian troops also were part of the coalition forces in Iraq and they still serve in the Nato-led force in Afghanistan.
AP said it could not independently verify the image but it bore markings consistent with a previous film.
Mr Hammond, referring to IS by an alternative acronym Isil, said: "If these reports are true, I condemn in the strongest terms the apparent brutal killing of Croatian national Tomislav Salopek by Isil in Egypt.
"My thoughts and condolences are with his family, colleagues and all the Croatian people.
"Britain will stand by Egypt and Croatia as we continue to oppose this inhuman brand of terrorism."