MOSCOW, June 16 (RIA Novosti) - Kosovo's new constitution is in violation of a UN Security Council Resolution, Russia's Foreign Ministry said on Monday.

Kosovo's new constitution came into force on Sunday after nine years of UN administration.

"This act [the entry of the constitution into force] continues a string of measures for the arbitral formalization of the territory's sovereignty and the policy of violating international law, only aggravating the tense situation in Kosovo and isolating the Serb population," the ministry's information and press department said.

The ministry said that Pristina, by declaring its intention to curtail cooperation with the UN mission in Kosovo, "is in gross violation of UN Security Council Resolution 1244 that assigns the central role in the Kosovo settlement to the United Nations."

Kosovo, with a 90% ethnic-Albanian majority, has been formally recognized as a sovereign state by 43 countries including the U.S. and most EU members since it proclaimed its independence from Serbia on February 17.

Serbian President Boris Tadic said on Sunday that Serbia does not recognize Kosovo's new constitution as its adoption will have negative consequences.

"For Serbia, it [the constitution] has no legal force. Serbia considers Kosovo as its southern territory. Serbia continues to defend its independence and sovereignty by peaceful means, with the help of diplomacy rather than force," Tadic said.

According to Tadic, Belgrade is continuing to insist on further negotiations on the status of Kosovo.

Russia and China back Belgrade's position that Kosovo must remain a part of Serbia.