ISIS linked jihadists claim beheading of Frenchman seized in Algeria

Jihadists linked to the Islamic State group claimed to have beheaded a Frenchman abducted in Algeria in a video posted online today, after Paris rejected their demand to halt strikes in Iraq.

Herve Gourdel, 55, was kidnapped on Sunday by Jund al-Khilifa, or 'Soldiers of the Caliphate,' while hiking in a national park that was once a magnet for tourists but later became a sanctuary for Islamists.

The purported beheading followed France's rejection of the group's 24-hour ultimatum to halt air raids in Iraq - part of a US-led campaign against the Islamic State (IS) group.

The video, entitled 'A Message with Blood to the French Government', employs a similar style to those used in previous videos by IS showing the beheadings of three Western hostages.

It begins with a clip of French President Francois Hollande at a press conference where he announced strikes against IS in Iraq.

The video then shows Gourdel on his knees with his hands behind his back in front of four armed militants with covered-up faces.

The Frenchman briefly expresses his love for his family before one of the jihadists reads a speech in which he denounces the actions of the 'French criminal crusaders' against Muslims in Algeria, Mali and Iraq.

The jihadist says the beheading is to 'avenge the victims in Algeria ... And support the caliphate' proclaimed by IS in Iraq and Syria.

There was no immediate confirmation from Paris about the authenticity of the video, which was posted on jihadist websites.

The United States has built a coalition of more than 50 nations to fight the IS organisation, after the jihadists seized large parts of Syria and Iraq and committed widespread atrocities, including beheadings and crucifixions.

France has ruled out joining military operations in Syria, where a US-led coalition began strikes against IS on Tuesday.

Prime Minister Manuel Valls, in a speech today that kicked off a parliamentary session about France's engagement in Iraq, vowed not to give in to blackmail.

"If we show weakness in the face of this threat, we encourage these cowards to continue their work of death," he said.

"We will stay committed... For as long as is needed for the Iraqi army to gain the upper hand over Daesh," he added, using an alternative name for IS.