Al-Qaeda’s North Africa branch says eight European hostages it is holding are alive.
In a statement on Twitter, al-Qaeda in the Islamic Maghreb (AQIM) said it would soon release a video of the captives.
Five of the hostages are said to be French, the nationalities of the others are not clear.
The statement came after rallies were held across France organised by families of four of the hostages.
The events in Paris, Saint-Cere, Nimes, Nantes and Orleans marked 1,000 days of their captivity.
“We would like to reassure the families and parents of the hostages of their children’s safety. We will soon, God willing, air a new video showing the five French hostages,” the statement said, reproduced on several jihadist websites.
It repeated previous statements by AQIM that the group would kill the hostages if France carried out any new military operations in North Africa.
France sent troops to Mali in January after al-Qaeda-linked militants threatened to over-run the capital, Bamako.
AQIM said it remained open to negotiations.
Thierry Dol, Daniel Larribe, Pierre Legrand and Marc Feret were kidnapped in Niger by militants in September 2010 in the town of Arlit while working for a French nuclear firm.
A video released in September 2012 provided the first evidence that they were still alive.
Mr Legrand’s grandfather, Rene Robert, told French TV on Saturday that “there have been a lot of missed opportunities, there has been a lot of time lost and it is time to bring this situation to an end”.
The fifth French hostage, Serge Lazarevic, was seized in November 2011 in north-east Mali.
Another Frenchman, Philippe Verdon, who was abducted with him was reported killed by AQIM in March this year. In its statement, the Islamist group confirmed his murder.
Correspondents say at least eight French citizens, a Dutchman, a Swede and a South African have been kidnapped in parts of the Sahara desert in recent years.
French President Francois Hollande stated in April that France would not pay a ransom for hostages.