The United Nations is appealing for calm following violence over the weekend in northern Mali where Tuareg separatists attacked government buildings. Deputy Secretary-General Jan Eliasson phoned Mali's President Ibrahim Boubacar Keita on Monday to express the U.N.'s extreme concern and condemnation of the violence in the northern city of Kidal, AP quoted U.N. spokesman Stephane Dujarric as saying. Separatist Tuareg rebels launched an assault on Kidal Saturday, storming government buildings, killing soldiers and civilians, and taking 30 hostages, officials said. Eliasson stressed the need to de-escalate tensions adding that the U.N. recognized that the attacks "had unleashed a strong emotional reaction in large parts of the population," according to Dujarric.