Police officers pass beside a demolished vehicle, during a violent protest of a group of ethnic Albanians in Skopje, Macedonia, Saturday, March 2, 2013. Hundreds of ethnic Albanians staged a contra-protest on Saturday to express support for the designation of the new defense minister. Police said Saturday at least 20 people, from whom 13 police officers and other mainly youngsters were injured in a series of scuffles that erupted late on Friday and continued over night when a group of a few hundred Macedonians started a protest against the designation of a new defense minister Talat Xhaferi, an ethnic Albanian and former rebel commander. AP Photo/Vangel Tanurovski A group of ethnic Albanians confront the police during a protest through a street in Skopje, Macedonia, on Saturday, March 2, 2013, as they show their support for newly named defence minister Talat Xhaferi, and as a contra-protest to Macedonian protests overnight Friday when scuffles broke out with police. A series of scuffles erupted late on Friday and continued over night when a group of a few hundred Macedonians started protesting against the designation of the new defense minister Talat Xhaferi, an ethnic Albanian and former rebel commander. The police use tear gas as a group of ethnic Albanians throw stones at them, during a violent protest of a group of ethnic Albanians in Skopje, Macedonia, Saturday, March 2, 2013. A woman passes beside a demolished vehicle during a violent protest of a group of ethnic Albanians in Skopje, Macedonia, Saturday, March 2, 2013. SKOPJE, Macedonia (AP) - Violent ethnic riots rattled Macedonia's capital, culminating on Saturday with hundreds raging through the city center, clashing with police, overturning cars and attacking a bus station. At least 22 people were injured, 13 of them police officers. Ethnic Macedonians kicked off the protests in Skopje on Friday, angry at the appointment of an ethnic Albanian defense minister, a former rebel commander during the 2001 conflict that pitted the country's two main ethnic groups against each other. Ethnic Albanians staged a counter-protest on Saturday, claiming that two Albanians were beaten and an Albanian flag burned Friday by ethnic Macedonians. Both protests turned violent, with ethnic Macedonians and Albanians taking turns to scuffle with police. Police spokesman Ivo Kotevski told The Associated Press that ethnic Albanians damaged two police vehicles and several private cars, and set fire to a bus on Saturday. He said 11 policemen were injured Friday and two on Saturday. Police said 18 protesters were arrested on Friday and Saturday, five of them minors. The incidents were mostly confined to the city center, but after ethnic Albanians scuffled with police, they spread to a northern sector of the capital, which has a heavy concentration of ethnic Albanians. The protests have died down, but masses of police are patrolling the streets of northern Skopje. Talat Xhaferi was named defense minister two weeks ago, sparking protests that escalated Friday. Most of the protesters were people in their teens and early twenties and police said they were promoted by organized groups of soccer fans. Xhaferi was a prominent rebel commander in the country's 2001 conflict, which simmered for nine months without breaking into full-scale war. It nonetheless claimed the lives of some 200 people, although there is no official tally. Since then, tensions between the majority ethnic Macedonians and Albanians, who make up a quarter of Macedonia's population, have abated but still flare up. Bujar Osmani, a spokesman for the ethnic Albanian Democratic Union for Integration, which is a coalition partner with an ethnically Macedonian party in the conservative government, appealed for calm. "People are creating tensions for their own political interests," he said, without specifying further. An association of ethnic Macedonian veterans from the 2001 conflict is trying to collect 150,000 signatures for a referendum to oust Xhaferi. But that looks unlikely because it would need parliamentary approval. The veterans' association has denied having anything to do with Friday's protest.