Kosovo's current status as a part of Serbia should be enshrined in a new constitution and voted for by Serbians, the country's prime minister has said.
Kostunica has told Serbs in Kosovo he will oppose independence
Speaking in Serbia's parliament, Vojislav Kostunica used strong rhetoric as he spoke about UN-brokered talks over the final status of Kosovo.
"We are being asked to humiliate ourselves as a state," he told MPs.
The UN and Nato have run Kosovo since military action against Serbia in 1999, and hope for a final deal this year.
A UN Security Council resolution on Kosovo calls for substantial autonomy for the province, rather than full independence.
Both Mr Kostunica and Serbia's President Boris Tadic have often spoken strongly in favour of maintaining Serbia's claim over Kosovo.
In parliament, Mr Kostunica said the approval of a new constitution would send a message that Serbia would not accept an independent Kosovo.
"For the state of Serbia, Kosovo will never be independent," he said.
"There will be no other answer from Serbia, as long as it exists."
Mr Kostunica referred to a 14th Century battle which cemented Kosovo's importance in the Serbian national psyche.
"Ever since those who lost their lives in Kosovo six centuries ago... Kosovo has always been and will always remain the constituent part of Serbia."
Mr Kostunica suggested that a referendum on a new constitution would encourage virtually all Serbians to vote, ensuring the result was valid and democratic.
Talks on future
Although it technically remains part of Serbia, Kosovo has been administered by the UN since 1999, when Nato air strikes drove out Serb security forces accused of persecuting the Albanian population.
Thousands of Kosovo's minority Serbs fled later amid sporadic clashes with the Albanian majority.
The security situation has improved, but Nato troops deploy to Serb areas when violence flares up again.
Diplomats say talks on the province's future, currently under way, are likely to bring some form of independence for Kosovo - as desired by the Albanians but opposed by the Serbs.