The Tuareg rebel leaders who signed a peace agreement with the Malian government in 2015 are being investigated by the public prosecutor.
The rebels have attacked Mali’s security forces in recent months and the government has referred to them as a terrorist group.
The investigation could lead to more violence in a region already under threat from fighters linked to al Qaeda.
The Tuareg rebellion in Mali’s north has been a source of conflict for decades.
In 2015, the Tuareg rebel groups signed a peace deal with the government that was welcomed by the United Nations.
However, some rebels have abandoned the agreement in recent months.
Analysts have warned that the fragile peace agreement may crumble.
The Malian junta is facing serious problems with terrorism and the rebels in the north.
The military recently seized control of the northern town of Kidal.
The military will focus on sustaining stability in the town and in central and southern Mali.