DAKAR, Senegal—A Mauritanian website said it received a video from al-Qaida's North African arm on Monday that appeared to indicate seven foreigners taken hostage in West Africa are alive.

The ANI website, which has previously been used by al-Qaida in the Islamic Maghreb, or AQIM, said the video was released three years to the day after four of the hostages, all French, were kidnapped from the French-operated Areva uranium mine in the northern Niger town of Arlit. It wasn't clear when the video was made, but ANI said recorded messages it contains from the French captives were made in June.

The other three hostages in the video were kidnapped from the northern Mali town of Timbuktu in November 2011. They are from the Netherlands, South Africa and Sweden.

The video was not released to the public or shown online.

AQIM was one of three Islamic extremist groups that took control of northern Mali following a military coup in March 2012. The groups were driven out following a French-led military intervention beginning in January.

One of the French hostages, 61-year-old Daniel Larribe, said on the video that his life had been endangered by the French military intervention, according to ANI. "I am in good health but threatened with death," Larribe said, adding that he held French authorities responsible for his fate. The three other French hostages are Pierre Legrand, Thierry Dol and Marc Feret.

The Dutch hostage is Sjaak Rijke, the Swedish hostage is Johan Gustafsson, and the South African hostage is Stephen Malcolm, who holds dual British citizenship. All three were kidnapped from a hostel in Timbuktu in an attack that killed a German man.

ANI said all the hostages appeared to be in good health.