The European Union has invited Belgrade to sign an interim political accord on February 7, appealing to Serbs to vote for a European future in Sunday's presidential runoff election.
Serbs will choose between Boris Tadic, the pro-European president, and Tomislav Nikolic, his pro-Russian opponent.
The 27 EU foreign ministers were unable on Monday in Brussels to agree on signing a full Stabilisation and Association Agreement with Serbia.
This was because the Netherlands insisted it must first show full co-operation with the UN war crimes tribunal on the former Yugoslavia.
Instead they agreed, after hours of debate, to sign an interim political agreement on co-operation covering free trade, visa liberalisation and educational exchanges.
EU denial
Javier Solana, the EU foreign policy chief, has denied charges that the bloc was interfering in the election.
"This is a text that will open up doors for Serbia to the EU," Dimitrij Rupel, Slovenia's foreign minister, told a news conference after chairing the meeting.
Slovenia holds the EU presidency at present.
Rupel said it was natural for the EU, which was built on "the negation of nationalism", to oppose nationalists in the Balkans.
The leaders of Kosovo's ethnic Albanian majority, who make up 90 per cent of the province's two million people, say they are within weeks of declaring independence from Serbia.
Real choice
Olli Rehn, the EU enlargement commissioner, said an interim deal on trade and travel should make the prospect of EU membership "real and tangible.
He said: "There's much at stake in Serbia in these days.
"The Serbian people are choosing between a nationalist past and a European future ... I trust the Serbian people will choose and indeed embrace their European future."
Vuk Jeremic, Serbia's pro-Western foreign minister, welcomed the offer when he met EU ministers just after the agreement.