Mali has sent troop reinforcements to an army base near the Algerian border, as skirmishes with Tuareg rebels threaten to develop into insurrection.
A Tuareg splinter group has turned its back on the 2006 peace deal
The army said one government soldier and seven Tuareg rebels were killed during the latest ambush on Sunday.
Col Abdoulaye Coulibaly said the rebels attacked government troops travelling to the remote town of Tinzaouatene.
Tuareg elders loyal to the government have gone to the area for talks with the leader of the rebel group.
The government in Bamako had been playing down the Tuareg attacks, to avoid publicising the insurgency.
But the increasingly-daring attacks on Malian troops, including laying siege on Friday to the army base in Tinzaouatene, prompted the Defence Ministry to rush reinforcements to the northeast.
Tuareg rebels also fired on a US military aircraft transporting supplies to Malian troops in the far north.
Mali receives military and financial support from the US Trans-Saharan Counter Terrorism Initiative to combat what the two governments say is the training of militant religious extremists in the desert.
Regional analysts argue that the US presence aggravates the situation.
Rebel groups rose up in Mali last year to press demands for inclusion in the political process and in the economic development of their desert region.
The Tuareg want a greater say in the development of the region
As the 'Tuareg Alliance' they reached a peace deal with the government in July 2006.
Malian officials claim that a breakaway faction, led by Ibrahim Ag Bahanga, is behind the latest attacks.
They accuse Ag Bahanga of leading what they call "armed bandits" whose aim is to protect lucrative smuggling routes across the Sahara.
But some observers say the Tuareg have taken up arms again because the Malian government failed to deliver on its promises.