BAMAKO (Reuters) - A Malian state prosecutor said on Wednesday that the Islamist militant group al Mourabitoun is suspected of kidnapping a French-Swiss aid worker from the city of Gao in northern Mali.

Sophie Petronin has not been seen publicly since Saturday, when men snatched her and drove off in a pickup truck. She ran a charity for malnourished children and had lived in Gao for 15 years, authorities said.

“The first indications show that she was certainly taken hostage by a terrorist group, al Mourabitoun,” prosecutor Boubacar Sidiki Samake told Reuters.

Al Mourabitoun has not claimed responsibility for the kidnapping. The group is led by Algerian militant Mokhtar Belmokhtar, who has been a prominent figure in insurgencies across North Africa and the Saharan border region.

Mourabitoun, al Qaeda in the Islamic Maghreb, and Ansar Dine have all conducted attacks in Mali this year from bases in the desert north.

Samake said he would start proceedings next week for high-profile attacks last year on the Radisson hotel in Bamako, the Byblos hotel in Sevare and La Terrasse restaurant in the capital. In all, about 38 people were killed.

Two Malians and a Mauritanian suspected of carrying out or planning the attacks would appear before a judge, Samake said.

A rebellion by ethnic Tuaregs in 2012 that sought to create a new state called Azawad was hijacked by militants linked to al Qaeda who seized northern towns and established sharia law.

French troops drove them out a year later but they still launch attacks and have spread to areas once considered safe, despite efforts by a 13,000-strong U.N. force to keep them at bay.

The separatist group, the Coordination of Azawad Movements (CMA), this week suspended its participation in a committee charged with implementing a 2015 peace accord.