Islamic State release video threatening to behead Croatian hostage

A video released by purported Islamic State militants claims they will behead a Croatian hostage in Egypt unless "Muslim women" held in prison are not released within 48 hours.

The video, which has been shared by IS sympathisers on social media, shows a man in a yellow jumpsuit kneeling before a man in military fatigues brandishing a large knife, the Associated Press reports.

The man in the jumpsuit identifies himself as Tomislav Salopek, a 30-year-old captured by ISIL fighters on July 22.

"I am married and I have two children," Mr Salopek says.

"They want to substitute me with the Muslim womens arrested in Egyptian prisons.

"This matter have to be achieved before 48 hours from now, if not the soldiers of Wilyat Sina will kill me."

Wiyat Sina is Arabic for an Egyptian group that calls itself the Sinai Province of Islamic State.

Late last month Croatian officials confirmed one of its nationals with the same initials had been kidnapped on his way to work in Cairo.

The video comes just days before Egypt unveils its highly-publicised extension to the Suez Canal.