Mali's army says it is investigating allegations that soldiers have carried out summary executions in the Islamist-controlled north.
A senior military officer told the BBC it was neither confirming nor denying such acts had taken place.
The International Federation for Human Rights has accused Malian troops of killing Arabs and ethnic Tuaregs because they did not have identity documents or simply because of their ethnicity
In a separate development, one of the main groups fighting in northern Mali says it has split and wants dialogue.
The Islamic Movement for Azawad announced it is breaking away from Ansar Dine, and is rejecting "all forms of extremism and terrorism".
Meanwhile, French warplanes have destroyed two rebel bases in Mali.
Military sources said the raids on Thursday targeted Ansongo, about 80km from the town of Gao in northern Mali, and another base nearby in what were described as very successful strikes.
More than 2000 Chadian soldiers and 500 troops from Niger are deployed at Ouallam in Niger, near the Mali border, to open a second front.
Meanwhile, France has ordered special forces to protect uranium sites run by Areva in Niger.