A female French aid worker has been kidnapped in Mali's restive north, the French foreign ministry has confirmed.

Sophie Petronin was abducted in the city of Gao on Saturday, the ministry said, adding that French and Malian authorities were working together "to find and free our compatriot as quickly as possible".

It was not clear who was responsible for the act, or why the aid worker was taken, according to a Malian commandant Baba Cisse.

"We immediately launched a search," a Malian security source told AFP news agency, without revealing how she was abducted.

"French soldiers of the Barkhane force (in Mali) are actively taking part in the search alongside the Malians," a French military source told AFP news agency without giving further details.

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A local radio station in Gao said the aid worker was affiliated with Aide Gao, a small nonprofit that helps children suffering from malnutrition. Petronin, who is in her sixties, had been working in Gao for a long time.

She was taken by a group of men who drove off in a Toyota pick-up truck, the radio station said.

Malian officials had reported the kidnapping of a woman with French and Swiss nationality in Gao, but there was as yet no confirmation that Petronin held dual citizenship.

Gao - seized by armed groups in 2012 before French forces drove them out a year later - is considered the best-secured town in northern Mali with multiple UN, French and Malian army checkpoints along main roads.

However, the offices of the UN peacekeeping mission located next to the airport terminal were razed by a truck-bomb explosion last month.

Mali's government signed a peace deal last year with secular armed groups, but fighters pledging allegiance to both al-Qaeda and ISIL have fought on and launched dozens of attacks on Western targets in recent months.

Source: News agencies