Four French hostages kidnapped in Niger in 2010 have been released, France's President Hollande has announced.
The men boarded a French government plane on Wednesday from Niger's capital Niamey. They are expected to be greeted by Mr Hollande in Paris.
The French defence minister said the four men were freed without a military assault or a ransom being paid.
They were seized on 16 September 2010 in raids targeting two French firms operating a uranium mine near Arlit.
The al-Qaeda in the Islamic Maghreb (AQIM) group said it was responsible.
Mr 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.
No further details of the release were given, but it is believed that Niger's top negotiator Mohamed Akotey, a former Tuareg rebel, obtained the release over the last few days.
Mr Akotey, who works with the French mining company Areva, is a respected figure in Niger.
The four men were identified as Thierry Dol, Daniel Larribe, Pierre Legrand and Marc Feret.
Mr Dol told the French news agency AFP that his time in captivity "was very difficult but it was the test of a lifetime."
"I'm happy, excited," Mr Legrand's aunt, Brigitte Laur, told AFP. "We waited for so long. After three years it's hard to believe."
They were all employees at the uranium mine run by the French nuclear company Areva.
"We can't say that they're in great health but their health is fine," said a source close President Hollande, quoted by AFP.
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.