The international peace envoy to Bosnia says the territorial integrity of the fragile Balkan state is under threat.
Valentin Inzko pointed to a rise in anti-state, secessionist rhetoric by Bosnia Serb officials.
Inzko highlighted Bosnian Serb efforts to dissolve Bosnia's armed forces.
Inzko made the comments to the UN Security Council on November 13.
In his 27-page report, Inzko singled out the president of the autonomous Serb Republic, Milorad Dodik, as "the most frequent, although certainly no the sole, proponent of (Bosnian) state dissolution."
Russia's UN Ambassador Vitaly Churkin said Inzko's report was written in "alarmist tones."
Churkin blamed Bosnia's Muslims for a rise in tensions.
Churkin also called for abolishing the Office of the High Representative and handing over authority to the Bosnians.
Bosnia has been ruled by a weak central government since the 1990s war that killed an estimated 100,000.
A 2010 election ended with political stalemate as leaders from the different ethnic groups failed to form a national government. The impasse was broken in 2011 although divisions remained.
Based on AP, Reuters and Itar-tass reporting