Romania and Cyprus have warned that they will not recognise any unilateral declaration of independence by Kosovo.
Mr Basescu says Kosovo could create a risky Balkan precedent
Romanian President Traian Basescu said recognition would send "a bad signal" which could not be justified and cast a shadow over the United Nations charter.
Cypriot Foreign Minister Erato Kozakou-Marcoullis said it could create a precedent in international relations.
Kosovo Prime Minister Hashim Thaci said recently a declaration of independence from Serbia could be made within days.
The United States and most EU countries are expected to recognise an independent Kosovo without approval from the UN Security Council. They back a UN special envoy's plan for internationally supervised independence.
Speaking on Thursday, Mr Basescu said Romania "will not be able to recognise a declaration of independence by Kosovo, irrespective of the labels such an act will have".
In addition to Romania and Cyprus, EU members Spain, Greece and Slovakia fear recognition could fuel separatist movements elsewhere.
Russia says independence should not go ahead until Belgrade agrees to it. Serbian leaders strongly oppose independence for UN-administered Kosovo, which broke away in 1999 after Nato intervened to stop Serb persecution of the majority ethnic Albanians.
The Cypriot minister, speaking in Finland, said her country's position was a matter of principle and of respect for international law.
"There's really no way that we can change our position," she said, insisting that the stance had nothing to do with fear of a reaction from Turkish-controlled northern Cyprus.
President Basescu rejected suggestions that ethnic Hungarians in Romania could take Kosovo as an example, but expressed concern about the response from pro-Russian separatists in Moldova.
The BBC's Oana Lungescu in Brussels says that as a neighbour of Serbia, Romania is keen to keep stability in the Balkans.