Bulgaria's Foreign Minister Ivaylo Kalfin urged Serbia on February 7 to push forward with reforms that would bring it closer to membership in the EU, saying the former Yugoslav republic could count on its backing to that end.

"Bulgaria supports closer ties between the European Union and Serbia, as well as speeding up the process that will bring Serbia into the EU, including by awarding it the status of an applicant country. We urge Serbia to jump-start the reforms needed for that as soon as possible," Kalfin said in a statement.

Serbia and the EU were due to sign a trade-and-visas agreement on February 7, but the country's nationalist prime minister Vojislav Kostunica blocked it at the last moment.

"It is regretful that the signing of this agreement was delayed because the Serbian cabinet could not reach a consensus on the issue. But I still hope that the government will accept the proffered hand, which will benefit Serbia and its people," Kalfin said.

Kostunica decided to veto the signing ceremony in Brussels, arguing that signing the pre-membership agreement with the EU would mean an admission that Serbia approved the EU's mission to Kosovo and the province's independence, the International Herald Tribune reported.

His pro-Western cabinet partners, allied to re-elected president Boris Tadic, are said to be furious with the last-minute change of plans, which could spell the end of the current cabinet. Kostunica called an emergency parliament session, expected next Monday, but is running out of time in his attempts to prevent Kosovo from declaring independence, which could come before the end of this month, The Guardian reported.

The EU offered the agreement, which focused on trade, visas and education, in the run-in to the presidential run-off in Serbia, which Tadic won by a slim margin.