A French man has been kidnapped in Algeria by a militant group linked to Islamic State (IS), French Foreign Minister Laurent Fabius has confirmed.

Herve Gourdel was seized on Sunday in the unsettled north-east Kabylie area.

Mr Fabius said an online video that showed Mr Gourdel flanked by armed men, calling on France not to strike IS militants in Iraq, appeared authentic.

He said France would do everything it could to liberate Mr Gourdel, but that the situation was "extremely critical."

Earlier, Islamic State militants warned they would target France - and other countries - after French jets launched air strikes in Iraq against the group.

IS jihadists have seized large swathes of territory in eastern Syria and across northern and western Iraq, forcing tens of thousands of people to flee their homes this year.

France's foreign ministry said in a statement: "We confirm the authenticity of the video showing images of French hostage Herve Gourdel, kidnapped in Algeria in the region of Tizi Ozou on Sunday."

"The threats made by this terrorist group shows once again the extreme cruelty of [Islamic State] and those who say they are affiliated to it."

Speaking in New York, where he is attending the UN General Assembly, Mr Fabius told reporters: "We will do everything we can to liberate hostages... but a terrorist group cannot change France's position."

The video shows Mr Gourdel flanked by two masked men.

The militants say they are members of the Algerian group Jund al-Khilifa, also known as Soldiers of the Caliphate.

The group has pledged allegiance to IS. Some reports have also described it as an al-Qaeda splinter group.

The militants said that they were responding to a call from IS to attack citizens of countries taking part in strikes in Iraq.

The apparent kidnappers threatened to kill Mr Gourdel unless France ended its military operation.

(BBC)