Al-Qaeda-linked rebels claimed a car bomb attack near a camp housing French troops as Malian and foreign forces battled to secure Mali's volatile north against Islamist fighters.
At least two civilians were wounded after a vehicle exploded just 500 metres (yards) from a camp occupied by French and Chadian troops in the city of Kidal, local officials said, in what appeared to be the first such attack in the conflict.
An official in the Kidal governor's office said the vehicle, apparently driven by a suicide bomber, was targeting the camp but exploded on Thursday before it reached the base, killing the driver.
The Al-Qaeda-linked Movement for Oneness and Jihad in West Africa (MUJAO), one of Mali's main Islamist groups, told AFP it had no difficulty getting into Kidal "to blow up a vehicle as planned".
"More explosions will happen across our territory," said MUJAO spokesman Abu Walid Sahraoui.
The spokesman said the group had sent fighters to Gao, where clashes with French-backed troops were taking place.
French-led forces, which launched an offensive in January, are increasingly facing guerrilla-style tactics after their drive to oust Islamists from the main northern centres of Gao, Kidal and Timbuktu met little resistance.
A military source said battles erupted overnight Wednesday in Gao, 1,200 kilometres (745 miles) from Bamako, after about 40 Islamists infiltrated the city.
The main courthouse was in flames, while Islamists briefly occupied the courthouse and Gao's city hall but French Defence Minister Jean-Yves Le Drian said Malian troops, backed by French forces, had repelled the attack.
Five Islamists were killed in the fighting, said Le Drian, speaking in Brussels. "The situation has returned to normal," he added.
The Malian army said the Gao clashes had left at least four Islamists dead near the courthouse, while two were captured. "On our side, we saw five injured," Modibo Naman Traore, a spokesman for the Malian army, said on public television.
MUJAO spokesman Sahraoui said the rebels were determined to recapture the city.
"Our troops have been ordered to attack. If the enemy is stronger, we'll pull back only to return stronger, until we liberate Gao," he told AFP.
Gao was retaken by French and Malian forces on January 26 during an intervention to dislodge rebels who had seized control of the vast desert north last year.
Mali's Prime Minister Diango Cissoko said this week that large-scale military operations in the north were winding down, but sporadic fighting has continued. A French legionnaire was killed on Tuesday in the mountainous Ifoghas region.
France's army spokesman Thierry Burkhard said that the "Panthere 4" operation in the Ifoghas had already left 30 Islamists dead since the start of the week.
Ethnic Tuaregs in northern Mali, who have long sought greater autonomy, initially backed the rebellion but later fell out with the Islamists and had retaken control of Kidal before the arrival of French troops.
About 1,800 Chadian troops were then deployed in the city as part of the West African AFISMA mission, which France hopes will eventually become a UN stabilisation force.
Asked whether it was coordinating its efforts with the main Tuareg rebel group, the MNLA, the French military said Thursday it was working with groups that shared its interests.
In Nouakchott, the capital of neighbouring Mauritania, dozens of Malian Arabs demonstrated to denounce abuses they said had been committed by Malian troops against light-skinned Malians, particularly Arabs, in the north.
The demonstrators, who spoke of arrests, torture and extra judicial executions of Arabs, appealed to the international community to intervene.
Thousands of Malians have fled west into Mauritania since the start of the French-led operation.
Human Rights Watch urged Bamako to act in a statement issued Thursday from New York.
"The Malian government should urgently investigate and prosecute soldiers responsible for torture, summary executions, and enforced disappearances of suspected Islamist rebels and alleged collaborators," it said.