Kosovo’s capital, Pristina, spiraled into brutal street violence Tuesday as police and protesters clashed over  a dispute with neighboring Serbia and what critics called inflammatory and derogatory comments made by a Serbian official about Albanians. At least 56 police were injured and 120 protesters arrested. Police used rubber bullets and tear gas to break up the demonstrations, which at their height consisted of more than 2,000 protesters, according to Reuters.

It was the second day of protests organized by opposition groups to the ruling government. They yelled that Trepča, a mining company in Kosovo that the government has tried to take over but is claimed by Serbia, is Kosovo’s property. Kosovo declared itself independent from Serbia in 2008, nine years after an ethnic conflict between Serbians and Albanians that forced NATO to intervene against the Serbian military. The mine has been under the direction of the United Nations since then.

The protesters also called for the offending Serbian politician, Communities Minister Aleksandar Jablanovic, to resign. Jablanovic called a group of Albanians “savages” for blocking the pilgrimage of a group of Serbs to a Kosovo monastery for Orthodox Christmas. He is one of three Serbian politicians in the Kosovo government. He apologized for the comments, but the dark history between Albanians and Serbs meant his apology fell largely on the deaf ears of Albanians, who make up 90 percent of the 1.8 million people who live in Kosovo. 2015-01-27T190442Z_1279652436_GM1EB1S08ES01_RTRMADP_3_KOSOVO-PROTESTS A protester takes part in a demonstration in central Pristina January 27, 2015. Riot police fought running battles with protesters hurling rocks and petrol bombs in Kosovo's capital Pristina on Tuesday in the worst unrest since the former Serbian province seceded in 2008. Photo: Reuters/Hazir Reka

Protesters broke windows of the main government building in Pristina on Monday and set trash cans on fire on Tuesday. Protest leaders called for Kosovo Prime Minister Isa Mustafa to nationalize the Trepča mines, which Mustafa promised to do before coming to power in mid-December. Mustafa received criticism from Western nations for the plan and has since rescinded on that promise. Some Albanian miners refused to come out of the mine until Mustafa said he would go ahead with nationalization.

One opposition leader, Fatmir Limaj, said on Monday that protesters wouldn’t stop until the government stepped down. On Tuesday, Mustafa accused the opposition of trying to take down the government and seize power by force.