The Malian government called for military support from former colonial power France last month. Control over northern Mali was lost to foreign rebels and al-Qaida groups following a coup in early 2012.
Human Rights Watch said it found evidence to suggest Malian forces exacted revenge on ethnic communities viewed as sympathetic to northern rebels.
"The Malian government needs to act now to put a stop to these abuses by their soldiers and appropriately punish those responsible," Corinne Dufka, senior West Africa researcher at Human Rights Watch, said in a statement from Nairobi. "Restoring security in the north means providing protection for everybody, regardless of their ethnicity."
Sebastian Elischer, an African researcher at the German Institute of Global and Area Studies, stated in a recent column in Foreign Affairs that ethnic Tuareg rebels, who fought alongside al-Qaida, may have fled across the border to Niger as French and Malian forces press north.
The European Commission said it responding to a crisis in Mali that's compounded by drought with more than $29 million in humanitarian assistance.