The separatist Serbian province is expected to unilaterally declare its independence on Sunday.
The sources said none of the EU member states objected to sending EULEX Kosovo mission, which comprises about 2,000 people, including 1,500 policemen.
Kosovo has been a UN protectorate since the NATO bombing of the former Yugoslavia ended a conflict between Albanian and Serb forces in 1999.
The Russian Foreign Ministry said on Friday that only the UN Security Council can make a relevant decision to change the format of the international mission in Kosovo.
"We are convinced that Security Council resolution 1244 is valid. And we draw the attention of our EU partners, who have said a great deal lately about their desire and decision to send an additional mission to the territory, that a change in the international makeup in Kosovo is possible only on the basis of a relevant decision by the Security Council," Mikhail Kamynin, a spokesman for the Russian ministry, said.
Although Kosovo's independence is backed by the United States and most EU countries, Serbia and Russia, among others, oppose the plans, considering any unilateral declaration of independence a violation of international law.
