Five people were killed in two car bomb attacks by Islamists on pro-autonomy MNLA Tuareg rebels in a remote Malian town bordering Algeria, a spokesman for the fighters operating said on Friday.
The attacks in In Khalil, some 1,700 km (1,050 miles) northeast of the capital Bamako, came a day after a car bomb killed two people in Kidal and French and Malian troops killed 15 Islamists on the streets of Gao.
Violence in northern Mali's towns underscore the risk of French and African forces becoming entangled in a messy guerrilla war as they try to help Mali's weak army counter bombings and raids by al Qaeda-linked rebels.
Moussa Ag Assarid, a Paris-based representative of the MNLA, said suspected Islamists had first tried to drive into a building, but the car was destroyed by fighters ahead of impact.
A second car then drove into the group's local operations centre and exploded.
Aside from the two bombers, Ag Assarid said three MNLA fighters were killed and three others wounded. It was not possible to independently verify the attack.
The MNLA swept across northern Mali in April, taking advantage of a power vacuum left by a coup in Bamako. But its revolt was eclipsed by a loose alliance of Islamist jihadists, including al Qaeda's North African wing, AQIM.
France is five weeks into an offensive to clear Islamist fighters from Mali's north, which Paris said risked becoming a springboard for attacks on the region and the West.
In the meantime, the MNLA says it has retaken control of Kidal and small towns around the Adrar des Ifoghas mountains, where many Islamists are believed to be hiding near the Algeria border.
France, which has established close links with Tuareg rebels on the ground, has set up a base at Kidal's airport and has kept a low profile in the town.
In Gao, the hub for French and Malian military operations in Mali's north, government troops carried out house-to-house searches on Friday after a day of fighting in which Paris said 15 Islamists were killed.