The United Nations mission in Mali said two peace-keepers were killed and two others seriously injured when a convoy hit a mine in the northern Kidal region. The mission said in a statement yesterday that the two injured peace-keepers were immediately evacuated after their vehicles hit the explosives about 15 kilometers outside Aguelhok. <br/><br/>A UN official said the peace-keepers were Chadian. UN Secretary-General Antonio Guterres condemned the attack and reiterated that attacks on peace-keepers may constitute war crimes under international law. <br/><br/>The peacekeeping mission in Mali is the deadliest of the UN's 16 global peacekeeping operations. Unidentified gunmen last month attacked the UN peacekeeping headquarters in Timbuktu, killing at least seven people and injuring others. <br/><br/>