Four French hostages kidnapped in Niger in 2010 have been released, France's President Hollande has announced.
He said the country's foreign and defence ministers "have left for Niamey" and the hostages would return home as soon as possible, the BBC reports.
The hostages were seized on 16 September 2010 in raids targeting two French firms operating a uranium mine near Arlit, northern Niger.
The al-Qaeda in the Islamic Maghreb group said it was responsible.
Hollande made the announcement during a visit to Slovakia on Tuesday.
Breaking from the script of the speech he was giving, he said: "I have some good news. I just learned from Niger's president that our four hostages in the Sahel, the Arlit hostages, have been released."
"I want to express all my gratitude to the President of Niger who obtained the release of our compatriots," he added, without providing further details.
A French diplomatic source said the four French nationals were still in the hands of the Niger authorities, but France's foreign and defence ministers had arrived in Niamey to welcome them, according to Reuters.
The four men worked at the uranium mine run by the French nuclear company Areva.
They were identified by the AFP news agency as Thierry Dol, Daniel Larribe, Pierre Legrand and Marc Feret.
Since their abduction there had been sporadic signs that they were alive, and a vocal campaign in their support was led by family members in France, the BBC's Hugh Schofield in Paris reports.
France's military intervention in neighbouring Mali earlier this year was a worrying time because of fears the hostages could be killed in reprisal, our correspondent adds.
During the military campaign French troops forced Islamists out of northern Mali, killing or scattering them across the vast Sahel region.
Security has been stepped up at Areva's Arlit operation, following an attack in May in which one person was killed and 14 injured.
Islamist militants claimed responsibility for the attack.