Moroccan Ali Maychou of the Group to Support Islam and Muslims (GSIM) was "the second most-wanted terrorist in the Sahel, including by the Americans", Florence Parly said aboard a government plane as she returned from an official visit to the West African region.

The GSIM has claimed responsibility for the biggest attacks in the Sahel since its official launch in 2017.

Comprising several jihadist groups linked to al-Qaeda in the Islamic Maghreb (AQIM), the GSIM alliance is led by a Tuareg Malian, Iyad Ag Ghaly, a 29-year veteran.

Ali Maychou was killed during the night of October 8 in Mali with the help of Malian troops and US support, Parly added.

He had joined al-Qaeda in the Islamic Maghreb (AQIM) in 2012 before co-founding GSIM with Iyad Ag Ghaly and masterminding its expansion in the Sahel.

The announcement came as Parly sought to reassure Mali of the support of European forces after a devastating jihadist attack last week that left dozens of soldiers dead.

The nation's military is struggling to contain an Islamist insurgency despite the help of forces from France, Africa and the United Nations, with a string of deadly assaults underscoring the fragility of a region where jihadist violence has claimed hundreds of lives.

Before leaving Mali on Tuesday, Parly expressed confidence that France -- which deployed its 4,500-strong Barkhane force in the Sahel in 2014 -- was nearing a breakthrough in its efforts to convince European partners to boost military assistance.

This would likely be in the form of training for the region's national armies.

Ali Maychou is the second GSIM key figure killed this year after French commandos killed jihadist veteran Djamel Okacha in February near Timbuktu.

US officials had accused him of kidnapping a number of Westerners in North and West Africa.