Serbia said it was hunting down rioters who torched the US Embassy in Belgrade Thursday as 120,000 protested the province's newly declared statehood.
Greece says former Yugoslav's state name – the same as a Greek province – is not acceptable.
The Serb-dominated area of Mitrovica is a flash point, and could be lost to Serbia.
Frustration is deep over Western support for independence that Russia sees as destabilizing and against international law.
Many educated, under-30 Kosovars are eager for the possibility of an independent country.
President Bush hailed the controversial move, as the EU and UN met to form their responses.