Sabre-rattling grows amid claims an attack is being planned on the territory's ethnic Serb areas.
Ethnic Serbs - who are in a majority in Kosovo's north - have recently staged mass protests against the government of PristinaThe Serbian army says it is at its "highest level of combat readiness" after weeks of escalating tensions between Serbia and Kosovo.
President Aleksandar Vucic says he will "take all measures to protect our people and preserve Serbia". The sabre-rattling is louder than ever and follows media claims that Pristina is preparing "an attack" on ethnic Serb areas in north Kosovo.But it has previously accused Mr Vucic of playing "games" to stir up trouble.The 27-member bloc is calling for "maximum restraint and immediate action", and for the leaders of Serbia and Kosovo to "personally contribute to a political solution".
Nato, which has peacekeeping troops in Kosovo, has called on all parties to avoid provocations. The EU has warned it will not tolerate attacks on EU police or criminal acts.