ALGIERS, Algeria - A splinter group from al-Qaida's North African branch kidnapped a French citizen and said Monday that it would kill him unless France halts it airstrikes against the Islamic State group in Iraq.
In a video that appeared on social media, a masked member of a group calling itself Jund al-Khilafah, or Soldiers of the Caliphate, addressed the threat to French President Francois Hollande and said the hostage would be killed unless the airstrikes were halted within 24 hours.
The group said it was answering a call by Islamic State spokesman Abu Muhammad al-Adnani to attack Americans and Europeans.
The French Foreign Ministry confirmed the authenticity of the video and identified the hostage as 55-year-old Herve Gourdel.
Hollande spoke with Algerian Prime Minister Abdelmalek Sellal by phone, the French president's office said in a statement, emphasizing the "total cooperation" between France and Algeria to try to find and free the Frenchman. It said authorities in the two countries were in constant contact.
French forces joined the U.S. on Sept. 19 in carrying out airstrikes against forces from the Islamic State group, which have overrun large swathes of Syria and Iraq.
Gourdel appeared in the video flanked by two masked gunmen and said he was taken hostage on Sunday and reiterated its demands that French airstrikes end.
The Jund al-Khilafah group broke away from al-Qaida's North African branch in recent weeks and has pledged allegiance to the Islamic State, which has emerged as a brutal rival to al-Qaida.
Al-Qaida in the Islamic Maghreb has remained loyal to the central al-Qaida movement, led by Egyptian Ayman al-Zawahri and located along the Afghan-Pakistani border.
The rise of groups claiming allegiance to the Islamic State group is the latest sign of al-Qaida's weakening influence in the face of its new rival's successes on the battlefield.
According to the Algerian Interior Ministry, Gourdel and two Algerian companions were driving through the mountains near the village of Ait Ouabane when they were stopped by a group of armed men Sunday evening.
The gunmen released the Algerians and took Gourdel, who the ministry said was a mountain guide. The three had spent the night at a ski lodge near the town of Tikdjda, 110 kilometers (65 miles) from the capital, Algiers.
On his Facebook page, Gourdel said last week that he was off to Algeria on a hiking and spelunking adventure and was looking forward to being guided himself for a change. He also joked about "if" he would return home from Algeria.
In a 42-minute audio statement released Sunday, Islamic State spokesman al-Adnani urged followers to kill Europeans and Americans, and "especially the spiteful and filthy French." The group has already beheaded two American journalists and a British aid worker.
"This threat to kill civilians, added to the execution of hostages and to the massacres, is yet another demonstration of the barbarism of these terrorists, justifying our fight without truce or pause," French Interior Minister Bernard Cazeneuve said Monday.
Prior to the kidnapping, France's Foreign Ministry issued a statement saying Foreign Minister Laurent Fabius had called on ambassadors in 30 countries - many in Africa and the Middle East, and including Algeria - to "invite our compatriots to reinforce their vigilance in the face of the terrorist risk."
Algeria has been battling Islamist militants since the 1990s and in recent years has confined them to a few mountainous regions in the north of the country and to the Sahara desert in the extreme south.
Al-Qaida in the Islamic Maghreb made millions of dollars over the last decade kidnapping Western tourists in the Sahara desert.
In January 2013, another al-Qaida splinter carried out a daring assault on an Algerian natural gas plant, taking dozens of foreign workers hostage, who were all later killed when the military retook the plant.