Dozens of people gathered in Mali's capital Bamako on Saturday to march in support of French journalist Olivier Dubois who was kidnapped by jihadists 100 days ago.

Dubois, who worked with several French media, said in a hostage video that the Group to Support Islam and Muslims (GSIM), the largest jihadist alliance in the Sahel, abducted him on April 8.

Mali has been struggling to contain an Islamist insurgency that first broke out in the north of the country in 2012 before spreading to the centre and neighbouring Burkina Faso and Niger.

Thousands of people have been killed and hundreds of thousands have fled their homes, while the economic impact on one of the world's poorest countries has been devastating.

Abductions have been frequent, both of Malians and of foreigners.

-It's been 100 days since Olivier was detained- said the mother of the journalist's two children, Deborah Al Hawi Al Masri, who was at the march.

-He is a walker and is part of a walking group- she said, explaining the idea behind the march.

Al Hawi Al Masri also said she felt it was her duty to draw attention to the case of a "journalist who was kidnapped because he wanted to inform us".

Friends and supporters of Dubois marched in a jovial mood, according to an AFP journalist, following a 5-kilometre (3-mile) route that the journalist often walked himself and that ended on the Niger River.

Many had donned white t-shirts bearing the slogan "#FreeOlivierDubois".

A similar rally took place in France's capital Paris on Friday. Supporters of the journalist also rallied in Paris and Bamako in June.

Dubois, a 46-year-old reporter who had been living and working in Mali since 2015, is the only known French hostage in the world.