Local Serbs gathered in front of the buildings to prevent Kosovo Albanian security forces and officials from entering and clashes broke out, media reported.
Kosovar police reportedly forced their way into the Zvecan municipal building, using tear gas and stun grenades. Telephone service was cut off in Leposavic, while alarm sirens sounded in the northern municipality of Mitrovica.
During the incident, about 10 citizens who had gathered to prevent illegal entry into the municipal building were injured and later hospitalized.
Earlier Friday, Serbian President Aleksandar Vucic placed the Serbian army on high alert in response to the situation in Kosovo and Metohija prompted by unilateral steps taken by Pristina. He also demanded that NATO "urgently stop violence against Serbs" in Kosovo and Metohija.
The latest comes amid a spike in unrest in the region following back-to-back mass shootings in Serbia, which saw Vucic call for a near "complete disarmament" of the nation. Although Serbia does have the third-highest rate of gun ownership, it maintains a low firearm-related homicide occurrence.
In early May, a 13-year-old shot at his classmates with a pistol and Molotov cocktails, killed eight students and a security guard. The day after, a gunman tore through two Serbian villages. He killed eight individuals and injured another 14 locals.