The Serbian-language media outlet "Alo.rs" published an article yesterday (June 13) with the claim in the headline that the situation in Mitrovica is tense and bursts of gunfire are being heard.
The article is based on a video footage showing the arrest of Milun Millenkovic.
In this video, the alarm sounded in north Mitrovica, the voices of citizens, and the sound of cars crashing can be heard.
Link to the article published by "Alo.rs":

The claim in the article's title about gunfire is not supported by the video included in the article. No gunfire is heard in the video.
Hibrid.info has not found any other media article reporting on gunfire yesterday (June 13) in northern Mitrovica.
An unverified claim of gunfire in northern Mitrovica was made yesterday (June 13) by the Albanian-language information portal "Jepi zë" by publishing a video material on Facebook with views showing a part of northern Mitrovica from above, which was handled by hibrid.info. (here)
Analyze:
Through a video footage showing the arrest of Milun Millenkovic, it was claimed that there were bursts of gunfire in north Mitrovica during the arrest.
In the released video, no gunshots are heard, but only sirens, people's voices, and the sound of cars crashing.
Based on its work methodology, hibrid.info considers this claim to be "misinformation".
Rating:
A “Disinformation” rating is given to media reporting that contains a “mix” of inaccurate sources or even half-truthful content. This rating will also address reports that have incorrect attributions or headlines that do not reflect the text in terms of information accuracy.