The Search for International Terrorist Entities (SITE) Intelligence Group reported the three-minute video on its website, in which the four male hostages can be seen sitting on the ground, with their armed captors standing behind them.
SITE tracks online activity of terrorist organisations. The video by Al Qaeda in the Islamic Maghreb (AQIM) - the North African branch of the terror outfit - is still being authenticated, French officials said.
The hostages said the video was recorded April 11, 12 and 13. AQIM, which operates across the Sahara, kidnapped seven people near a uranium mine in Niger in September 2010.
In February, the group released a French woman, a citizen from Togo and one from Madagascar. French nationals Pierre Legrand, Daniel Larribe, Thierry Dol and Marc Furrer are still being held.
Published 27 April 2011, 12:22 IST