At one point during her four years in the hands of jihadist militants in northern Mali, French aid worker Sophie Petronin said she felt like giving up hope. She wandered into the desert, sat on the ground in the baking sun and wept.

The 75-year old, who ran a charity for malnourished and orphaned children when she was kidnapped near the desert city of Gao in late 2016, was one of four hostages released and flown to the capital Bamako late on Thursday.

She said snippets of news from home had provided comfort while in captivity and that she was able to find the strength to endure her ordeal when a small voice in her head spoke to her.

“It said you mustn’t cry or be sad. I will stay with you. And until today it hasn’t left,” Petronin told journalists.

Petronin’s son, who was there to greet her on the tarmac at Bamako airport on Thursday, lifted her from the ground as he embraced her. She is due to return to France on Friday.

There are at least six foreigners still held by Islamist groups in West Africa’s Sahel region, where thousands of international troops are struggling to curb the growing reach of the insurgency in the vast desert borderlands.

Another of the freed captives, Malian politician Soumaila Cisse, described his sense of loneliness and hardship after he was seized by gunmen on the campaign trail in the northern region of Timbuktu in March.

“I spent six months in conditions you can’t imagine, extremely difficult conditions - in semi-permanent isolation,” Cisse told journalists, wearing white robes and a face mask.

Petronin said a doctor had given her a clean bill of health, although she has lost some weight and four teeth.

“We’ve all had or will have trials to go through. If you don’t accept what happens, it will be too hard,” she said. “I almost turned it into a spiritual retreat.”