Ahead of her trip to the Balkans this week, Chancellor Angela Merkel is to force home the message that Serbia must make its peace with Kosovo, if it wants to join the European Union. In a regular Saturday podcast, the chancellor said she understood that scars in the region run deep but stressed there would be no EU perspective for any country without the will "to work well with neighbours, respect them and resolve conflicts peacefully." She is expected to bring the point across to President Boris Tadic, who has led the increasingly shaky pro-European coalition government since 2008. But Merkel warned in her address Saturday that such a scenario "naturally does not come without conditions." While in Croatia, first on her agenda, the chancellor is to congratulate the country''s leaders on its completion of EU accession talks earlier this year, Merkel will face a less pleasant task in Belgrade. During her trip to Serbia, where she is scheduled to arrive Monday evening and remain until Tuesday, Merkel is to clarify that the country''s EU aspirations are not compatible with its rocky relations with Kosovo and ongoing hostility in the region, government sources said in Berlin. While ethnic Albanians make up the majority of the population in Kosovo, ethnic Serbs dominate its northern region. Talks between Belgrade and Pristina aimed at resolving problems stemming from the secession, including trade and energy, stalled in July when simmering tensions escalated after Belgrade refused to open its borders to goods from Kosovo. The resulting trade war ended in violence and the death of a Kosovar policeman when the government in Pristina ordered police to seize control over border crossings in the north in order to impose a trade ban on Serbian goods. A further escalation was prevented by the NATO peacekeeping mission, KFOR, which provisionally assumed control over the borders and brokered a deal between Belgrade and Pristina - which has, however, yet to be fully implemented. The German chancellor is to reiterate that the borders in south-eastern Europe cannot be changed. Kosovo declared independence from Serbia in 2008, but Belgrade refuses to accept it. Serbian officials have also floated the idea of an ethnic partition of Kosovo, in which the mostly Serb north would join Serbia proper. While German officials said that Serbia does not have to recognize Kosovo to begin moving closer to EU, they insist that progress in talks with Pristina - which began in March and are mediated by the EU - and a normalization of relations in the region are essential. Merkel is to press for progress in the trade chapter of the talks, which are expected to resume early next month, and on the implementation of the agreement that will allow KFOR to hand over control of the border checkpoints in mid-September, as planned. With polls due in 2012 and under the pressure of economic crisis and growing Euro-scepticism at home, Tadic hopes that the EU will officially recognize Serbia as a membership candidate in October and simultaneously determine the date for the start of the accession talks.