The rebel alliance, called the Coordination of Azawad Movements, CMA, has been fighting the army since August, a conflict unleashed in part by the departure of a United Nations peacekeeping mission that for years had helped maintain a fragile calm.
But clashes appear to be intensifying as both sides seek to control territory in areas recently vacated by the U.N. Bourem is just 90 km (55 miles) north of the strategic city of Gao.
The general staff of the Malian armed forces said 10 combatants on its side were killed on Tuesday repelling an attack near Bourem and said 46 enemy fighters had been killed during the operation.
The CMA said in a statement on Wednesday that it had lost nine fighters and had killed about 97 Malian soldiers. The group, formed by semi-nomadic Tuareg people, said it had attacked four army positions around the town of Bourem and made away with vehicles, weapons and ammunition.
CMA spokesperson Mohamed Elmaouloud Ramadane earlier told Reuters that the rebels had briefly seized control of a military camp in Bourem, but later retreated.
"I confirm the CMA took control of the camp around 10 a.m. after very violent fighting," he said on Tuesday. Reuters was not able to confirm independently what happened or any death toll.
The general staff did not mention the camp or refer to the CMA by name, but said the situation around Bourem was under control. Surviving rebels withdrew toward the north, its statement late on Tuesday said.
The Tuaregs have long complained of government neglect and sought autonomy for the desert region they call Azawad. A Tuareg uprising in 2012 was taken over by Islamist groups that continue to attack civilians and the army.
The CMA signed up to a peace deal with the government and pro-government militia in 2015. But tensions have resurfaced since the military consolidated power in two coups in 2020 and 2021, teamed up with Russian military contractor Wagner Group, and kicked out French forces and U.N. peacekeepers.
Peace has never been easy — tensions have often arisen between northern armed groups and the army since 2015, and last year a coalition of groups pulled out of talks.
Conflict between the army and the rebels could worsen an Islamist insurgency in Mali, where groups linked to al Qaeda and Islamic State control large areas.