The so-called ’Islamic State of Iraq and the Levant’ (ISIL) takfiri group claimed Wednesday it has beheaded a Croatian hostage, and released a picture of a body after what would be the first such killing of a Westerner in Egypt.

The so-called 'Islamic State of Iraq and the Levant' (ISIL) takfiri group claimed Wednesday it has beheaded a Croatian hostage, and released a picture of a body after what would be the first such killing of a Westerner in Egypt.

Croatian Prime Minister Zoran Milanovic told reporters he could not "confirm with 100 percent certainty" that Tomislav Salopek, who worked for French company CGG, had been murdered.

"But what we see does not look good," he said, adding that his government would not give up searching as long as there was hope.

Salopek was abducted last month west of Cairo. The terrorist group had issued a 48-hour deadline that expired on Friday threatening to kill him if Muslim women prisoners were not freed from Egyptian jails.

The authenticity of the picture could not be immediately verified.

Salopek's abduction and purported killing were unprecedented in Egypt, which is battling an ISIL insurgency in the eastern Sinai Peninsula.

Although ISIL's Egyptian affiliate has killed hundreds of policemen and soldiers since the army overthrew Muslim Brotherhood president Mohammad Mursi in 2013, the country had been spared the gruesome kidnappings and executions of foreigners by the terrorists in Iraq and Syria.

The group has in the past beheaded Bedouin in Sinai it accused of collaborating with the army.

State-run Croatian news agency HINA quoted a foreign ministry source Wednesday as saying it "does not have confirmation that abducted Croatian citizen Tomislav Salopek has been killed".

The picture was posted on ISIL-affiliated Twitter accounts with the caption: "Execution of prisoner from Croatia - which has participated in war on Islamic
State -- after deadline ended."

Britain condemned the "apparent murder" of Salopek, 31, and France called it a "despicable assassination".

French Foreign Minister Laurent Fabius said if Salopek's death was confirmed, "this despicable assassination again confirms the cowardly, barbaric nature of this terrorist organization".

Egypt had said it was intensifying efforts to locate Salopek after IS released a video of him last Wednesday.

Cairo-based Al-Azhar condemned the reported beheading.

"The killing of the Croatian hostage is a Satanic action that has nothing to do with religions and traditions," Al-Azhar said in a statement.

Salopek's abduction had been treated by police as a criminal kidnapping before the video emerged.