Two UN peacekeepers were shot dead and a third slightly wounded by one of their colleagues in northern Mali, the UN mission said on Sunday, less than three weeks after a similar incident.

"Yesterday (Saturday) at around 1900 GMT a tragic incident occurred in the MINUSMA camp at Tessalit, in the Kidal region in which a peacekeeper fired on three of his colleagues," a statement from the MINUSMA mission said, without giving the nationalities of the peacekeepers.