Police in Kosovo made more than 140 arrests after protesters at two border crossings tried to stop traffic from Serbia entering the territory on Saturday.
Around 50 people, mostly police officers,were injured.
The protesters say Serbia wants to obstruct development in Kosovo, which declared independence from Serbia in 2008.
Serbia does not recognise the independence of the territory.
The demonstrations were organised by Self-Determination, a Kosovo party opposed to contacts with Serbia.
''Serbia is the enemy of the Kosovo state and our motto is 'Serbia will not pass','' said said party leader Albin Kurti.
The BBC reports both border crossings were still open several hours afterwards, but riot police were still there.