Mali unrest: Kidal's deadly race riots
At least one person has been killed in Mali's northern town of Kidal, following ethnic clashes between Tuaregs and black civilians, ahead of elections next week.
Tuareg rebels held the town until a June deal with the government.
The BBC's Alex Duval Smith in Mali says it remains unclear who is really in charge of the town.
Many Malians blame Tuareg separatists for starting the 2012 rebellion which led Islamists to seize northern areas.
The fiercest critics of Mali's planned presidential election say the process will cut the country in two - thus completing, politically, the job left unfinished by Islamist militants when the French intervened against them in January.
Every security incident in Kidal is grist to the critics' mill because it makes it less and less likely that the terrified population of the town - and of all but the major urban centres in the north - will venture out to vote on 28 July.
The large number of people displaced by the war - who are unlikely to be able to cast ballots in large numbers - will add to the north's voicelessness.
A ceasefire agreement signed in Ouagadougou last month aimed to create conditions for the MNLA rebels and the Malian authorities and army to coexist in Kidal - under the watchful eye of United Nations and French troops - in the run-up to the election. But the deal was naive; without prior reconciliation, the poll may deepen hostilities.
On Wednesday, Tiebele Drame, Mali's negotiator in Ouagadougou, pulled out of the presidential race in protest at the shortcomings of the electoral process.
He says the population of Kidal is being held hostage to a ''botched'' election forced upon Mali by the international community.
French and West African forces intervened in January to force the Islamist militant groups out of the desert towns but security remains a concern.
Elections are being held on 28 July in a bid to restore civilian authority over the country.
It is not clear what started the clashes in Kidal but witnesses say shots were fired and a member of the Songhai community was killed by Tuareg youths, who also set fire to black-owned shops.
Local military commander Colonel Didier Dako said soldiers had been deployed in the town to quell the violence, reports the Reuters news agency.
Since arriving in Kidal last month, the soldiers had been confined to barracks in order to avoid confrontation with the local population and the rebels.
Some of the youths reportedly shouted: "Long live Azawad" - in support of the rebel call for independence for northern Mali.
Under the June deal, fighters from the National Movement for the Liberation of Azawad (MNLA) are allowed to remain in the town but they are supposed to disarm.
Kidal is the only town in Mali where the light-skinned Tuaregs form a majority.
The Tuaregs have launched several rebellions since Mali's independence in 1960, accusing the government in Bamako of ignoring the northern areas where they live.
The MNLA had been allied to the al-Qaeda-aligned groups in early 2012, but the alliance crumbled as the Islamists gained control of most of the territory in the north.
The Tuaregs captured Kidal after the French-led offensive forced the Islamist groups out of northern towns in January.
Earlier this week, one of the 28 registered presidential candidates pulled out of next week's election, saying the authorities were not in a position to hold the poll.
Analysts say that Mali's state had all but collapsed after a military coup in March 2012, which helped the rebels to extend the areas under their control.