The president of Mauritania, Mohamed Ould Cheikh El Ghazouani, called for the return of Mali to the G5 Sahel organisation.
Mali left the regional military alliance fighting jihadist groups in May last year citing "loss of autonomy" and "instrumentalization" within the organisation.
The appeal took place on Monday in the Mauritanian capital, Nouakchott, at the opening of the 4th session of the General Assembly of the Sahel Alliance, a platform of 27 bilateral partners and donors set up to mobilise international aid for the development of the region.
The junta that has ruled Mali since 2020 has broken with France and its allies turning to Russia for help.
Mauritania, a vast, mostly desert country with a population of 4.5 million, has not seen any attacks since 2011.