BRUSSELS -- Serbian President Aleksandar Vucic refused to hold face-to-face talks with his Kosovar counterpart, Hashim Thaci, as mounting tension cast new doubt over prospects for a landmark agreement between the countries and the normalization of ties.
Amid talk of land swaps between Serbia and Kosovo, Vucic and Thaci had been expected to meet in Brussels on September 7 for talks moderated by European Union foreign policy chief Federica Mogherini.
A spokesman for Vucic said that the president made the decision because of what he claimed were "lies, deceits, and threats" from the Kosovar side, and the two heads of state ended up meeting separately with Mogherini.
Speaking to the media after his meeting with Mogherini, Thaci said it was "now clear that the more we move forward, the whole thing is becoming more difficult" and that the difference between the two sides is "becoming bigger."
"In theory, there is the possibility of an agreement, but now we are going through a period of reflection," he added.
The EU-moderated normalization talks in Brussels were the first since August, when the pair floated the idea of territory swaps to reach a deal that can move both Belgrade and Pristina closer to EU membership.
Before entering the talks, Thaci expressed support for incorporating the Presevo Valley, an ethnic Albanian-majority region of southern Serbia that is adjacent to Kosovo.
"The whole society in Kosovo, including institutions and civil society, is in favor of dialogue and in favor of agreement with Serbia, as well as in favor of a demarcation line with Serbia that is 430 kilometers long and that also includes [the Presevo Valley]."
EU foreign policy chief Federica Mogherini (left) speaks with Serbian President Aleksandar Vucic in Brussels on September 7.
According to the proposal under discussion, the Presevo Valley area would be transferred to Kosovo, while the predominantly Serb-populated northern part of Kosovo around the city of Mitrovica would pass to Serbia. The idea of a land swap is strongly opposed by nationalists in both countries.
Vucic made no comment to the media in Brussels, but the Serbian director for the Office of Kosovo, Marko Djuric, told journalists that “because of all the lies and deception and the disgusting approach that the representatives of Pristina showed toward the Serbian side over the past couple of days...President Vucic will not meet them today here in Brussels."
He said that both Vucic and his 16-year-old daughter had received threats, but did not elaborate.
"It is a big question if and when we will continue talking with these people or with someone else in the future who is much more understanding," Djuric said.
The current tensions stem in part from a proposed visit by Vucic to the Gazivoda Lake area in northern Kosovo, where Vucic had announced he would deliver a speech to ethnic Serbs on September 9.
After the Brussels talks concluded, Mogherini issued a statement saying that "all issues" were on the table.
"Difficulties remain," she said. "I trust the full commitment of both presidents to continue the process and reach in the coming months a legally binding agreement on comprehensive normalization of relations, in line with international law."
She also noted that the next meeting was expected to take place in Brussels before the UN General Assembly starts in New York at the end of September.
Kosovo declared independence from Serbia in 2008. Although more than 100 countries recognize Kosovo, Serbia does not.
Both countries have been told they must resolve their differences in order to make progress toward EU membership.