Nine people were injured Saturday when someone threw an explosive device into a popular cafe in the Kosovo town of Mitrovica.
One person has been detained in the attack.
The ethnic Albanian and Serbian sections of Mitrovica are separated by a river. Serbian leaders in Kosovo called on authorities to close the bridge that spans the river, connecting the two parts of town.
NATO peacekeepers and international police have repeatedly been deployed at the bridge to prevent outbreaks of violence. Mitrovica has been the scene of violent clashes between the two communities since the United Nations took over administration of Kosovo in 1999.
The government of Kosovo called on citizens to stay calm and not become prey to provocations.
Kosovo's ethnic Albanian majority is seeking full independence from Belgrade, while Serbian authorities want to keep at least some control over the province. U.N.-brokered talks with the two sides have failed to bring about a compromise.
Saturday's explosion comes a day after the top U.N. mediator on Kosovo ended a visit to the region.