At least 20 people have been killed when Tuareg fighters attack an army post close to Mali's border with Mauritania.
The defence ministry said in a statement that Saturday's attack targeted an army outpost in the town of Nampala, located around 500 km northeast of the capital, Bamako.
The dead include nine security personnel and 11 assailants, with many more injured, the statement said.
The attack is likely to test a five-month ceasefire in the large, gold-producing West African nation.
Armed men in more than 20 four-wheel drive vehicles raided the post at Nampala, some 400km northeast of the capital Bamako before dawn, one source said.
Hours after the attack, the rebel Tuareg Alliance for Change of Northern Mali, known by its French acronym of ATNMC, posted a statement on its website claiming responsibility for the incident.
Rebel spokesman Hama Ag Sid'Ahmed said in the statement the attack was intended to force the government into dialogue.
"So that we can move beyond the current impasse which has lasted for the past three years, we want the Malian authorities ... (to reinitiate) a real dialogue," the rebel statement said.
In July, Algeria brokered a ceasefire between Mali's government and the Tuareg rebels.
For more than a year Tuareg fighters have attacked army posts and convoys to press for greater rights for their people in the largely desert West African country.
But doubts remain about the participation of Bahanga, a veteran rebel chieftain seen as something of a rogue element in the Malian Tuareg uprising.