Serbia and ethnic Albanian leaders have restated their entrenched positions over Kosovo's future status at last-ditch talks in Austria.
Negotiators have failed as yet to reach a compromise
Ethnic Albanian leaders said they would not back down from their demand for full independence from Serbia.
Belgrade said it would not give up "an inch" of the province.
The two sides, with mediation from the European Union, Russia and the United States, have until the UN deadline of 10 December to clinch a deal.
Kosovo - currently part of Serbia - has been administered by the UN since 1999, when a Nato assault drove out Serb security forces accused of repressing the ethnic Albanian majority.
"Serbia will not let an inch of its territory be taken away," Serbian Prime Minister Vojislav Kostunica told reporters before the talks began in Austria's spa town of Baden.
He added that Serbia was "a sovereign, free, democratic and internationally recognised state".
Meanwhile, Kosovo's Prime Minister-designate Hashim Thaci told Reuters that the Baden talks would be "the last meeting, after two years of talks".
"We can negotiate for 100 years more with Serbia but for the independence of Kosovo we can have no compromise," Mr Thaci, a former ethnic Albanian rebel leader, added.
Earlier rounds of talks have failed to reach agreement, and there is little hope of a breakthrough now, the BBC's Bethany Bell in Austria says.
Kosovo's attempts to break away have the backing of the US, while the EU is split on the issue.
Russia supports Serbia, saying an independent Kosovo would be illegal.
Some countries fear independence for Kosovo could encourage ethnic separatism in other regions.