The Malian army was redeployed from Gao to the northern region of Kidal on Monday, according to two security officials who spoke under condition of anonymity.
The convoy of 119 vehicles left Gao on Monday morning heading towards the Tuareg rebel stronghold which lies 300km to the northeast of the city.
The decision to move was taken on Sunday evening at a meeting of national security chiefs, the officials said.
The north of Mali has seen a resurgence of hostilities by predominantly Tuareg rebels against the Malian army since the end of August.
In 2012, the armed separatist groups rebelled against the state but signed a peace deal - known as the Algiers agreement - with the government three years later.
The deal came under strain, however, in 2020, following a coup which toppled the civilian government.
Since coming to power, the junta, led by Assimi Goïta, has made the re-establishment of state control over the area one of their central aims.