Updated

The United States has strongly condemned the recent friction between Kosovo and Serbia, saying it could "unnecessarily heighten tensions and threaten regional stability."

Marko Djuric, the head of the Serbian government office for Kosovo, was briefly detained in the divided town of Mitrovica on Monday because he entered the country without Kosovo's official approval. He was expelled under police escort.

The following day, Russia became involved in the dispute and the European Union sent its foreign policy chief Federica Mogherini on an urgent trip to Belgrade.

A statement from the U.S. Department of State Wednesday urged all parties to avoid further escalation and resolve disputes peacefully.

Kosovo declared independence from Serbia, against Belgrade's wishes, in 2008.