"The use of international police and activities against Serbs is unacceptable," spokesman Andrei Nesterenko said.
Nesterenko said that there is a growth in the destabilization of northern Kosovo that could lead to an escalation of tensions throughout the region, adding that "balanced actions in the interests of all parties are needed."
Kosovo's minority Serb population, which is dominant in the north of the territory, began to protest last week in Brdjani, an Albanian area within the Serb part of the divided city of Mitrovica, to prevent houses from being rebuilt which had belonged to ethnic Albanians who were forced out during the war in 1999.
The Serbs demand a ban on the return of ethnic Albanians until the same opportunity is provided to Serbs in the southern, Albanian-majority part of Mitrovica, which is split into mainly Albanian and Serb sections by the Ibar River.
On Monday, tensions flared when EU police, backed by the NATO-led peacekeeping force (KFOR), fired teargas at Serbian demonstrators attempting to enter an ethnic-Albanian area of Mitrovica.
"We had a couple of incidents today in Mitrovica - one in Brdjani, one at the bridge - and afterwards two hand grenade attacks - one against our police officers and another against KFOR," Christophe Lamfalussy, a EULEX spokesman in Kosovo, was quoted by Deutsche Welle as saying on Monday.
KFOR took control of Brdjani on Monday, entering the area with tanks and heavy machinery.
Kosovo declared its independence from Serbia in February 2008, but has only been recognized by 56 of the 192 UN member states.
