On the banks of the River Niger, mud-walled buildings festooned with tricolours mark out the ancient trading post of Gao, Mali's largest northern city where the French have been welcomed as heroes. It is barely two months since Mali's former colonial power sent troops in to take back its cities from Islamists who had seized power in a devastating push which saw them gain control of the war-torn west African country's entire north.

The UN's human rights body on Tuesday accused Malian soldiers of carrying out retaliatory attacks that appeared to target specific ethnic groups, and demanded that Mali investigate and bring the perpetrators to justice. The preliminary findings of a UN mission to Mali last month showed "that the recent military intervention in the north of Mali was followed by a serious escalation of retaliatory violence by government soldiers who appear to be targeting members of the Peuhl, Tuareg and Arab ethnic groups," UN Deputy High Commissioner for Human Rights Kyung-wha Kang said.

Chad's 2,000-strong contingent in Mali, which has played a leading part in the fight against jihadist militants, on Saturday officially joined the regional African force deployed there. "As of today, our Chadian brothers who are fighting to liberate Mali are joining AFISMA," Ivorian army chief Soumaila Bakayoko, whose country currently chairs the regional bloc ECOWAS, told reporters. "This is good news, it will strengthen cohesion," he said after meeting his counterparts in Dakar.

BAMAKO, March 7 (Reuters) - France's Defence Minister Jean-Yves Le Drian paid a surprise visit on Thursday to French forces battling Islamist rebels in rugged northern Mali, saying their military mission would not end until security was restored in the West African country. After reviewing ranks of French soldiers near the desolate Adrar des Ifoghas mountains, Le Drian told France 24 television that Paris' aim was to help "reestablish security in the whole of Mali's territory".