Ethnic Albanians protested in southern Serbia on Saturday after Serb officials said border guards killed a 16-year-old Albanian who was illegally crossing the border with Macedonia. The killing took place on Friday in Serbia's Presevo Valley, an Albanian-majority area east of U.N.-run Kosovo that was the scene of an ethnic Albanian insurgency in 2000-01. "The first results of the investigation show this was an attempt to illegally cross the border and border authorities reacted in accordance to the rules," Serbian Defence Minister Prvoslav Davinic told reporters in the town of Bujanovac. He said there would be a full investigation to establish if there was any negligence or error on the part of the army. Officials did not say if the teenager was leaving or entering Serbia. Local Albanian leaders said he was on his way back to Serbia from Macedonia and that the stretch of border was a favourite spot for illegal crossings to ethnic Albanian villages on the Macedonian side. --Mor 2150 Local Time 1850 GMT