Increased police presence in ethnic Serb-majority municipalities in Kosovo following several incidents in recent days has sparked further tensions between Belgrade and Pristina.
The spike in hostilities was launched by Pristina's call for snap elections in four Serb-dominated communes in the north.
The Serbs in the north reject Pristina's authority and Kosovo's independence from Belgrade.
The elections, scheduled for 18 and 25 December, were prompted by the abandonment of local posts by Serb minority representatives, in another sign of spurning the authority of Prime Minister Albin Kurti and his government.
The mass departure in November -- estimated to have involved more than 600 officials and police officers -- was caused by the ongoing licence plate row between Kosovo and Serbia.
The months-long political standoff over a government decision to force a replacement of Belgrade-issued car licence plates with domestic ones resulted in large-scale protests, but also property damage and attacks on Kosovo law enforcement officials, according to the government in Pristina.
Kosovo police on Friday said one officer was injured by gunmen after increasing its presence.
A police officer was "slightly wounded,” and a police car was damaged after armed men fired from a vehicle in the village of Sërboc/Srbovac, in the municipality of Zveçan/Zvečan, 50 kilometres north of the capital Pristina, a statement said.
The injured officer was taken to the hospital and police are investigating the case.
Earlier this week, some local electoral committee offices were damaged, and shooting was heard in those communities, raising fears of further escalation of the long-simmering tensions.
Kosovo police said explosions were heard and shots fired on Tuesday
Read more on euronews.com