EU foreign policy chief Federica Mogherini has urged Belgrade and Pristina to "swiftly deliver," and "refrain" from actions contrary to normalization efforts intended to lead to formal EU accession talks for both Serbia and Kosovo.
Last Monday, Kosovo imposed an import tax of 10 percent on produce from Serbia and Bosnia, claiming it was "protecting" local industry and retaliating for Belgrade's non-recognition of its former province.
At Thursday's talks in Brussels, also attended by Kosovo President Hashim Thaci, Serbian President Aleksandar Vucic said his officials would "not show up" until Pristina withdrew the tax, adding that it violated a regional, non-EU trade pact.
It was not immediately clear when the presidents would next meet. They first met in July, and a scheduled meeting in September fell through.
'Aggressive and arrogant'
Vucic has criticized Kosovo's plan to create an army, a move also opposed by the ethnic Serbian minority in northern Kosovo.
Thaci has described Serbia's attitude as "aggressive and arrogant," adding that dialog was difficult "but we should work upon that."
Ahead of Thursday's meeting, Thaci had tweeted plans to "reconfirm Kosovo's full commitment to achieve a legal binding comprehensive agreement with Serbia."
Kosovo, with its 90-percent Albanian majority, declared independence form Serbia in 2008, 10 years after a 1998-99 war between Serbian forces and separatists that led to NATO intervention.
Serbia still refuses to recognize Kosovo's independence, although some 110 nations have done so — not including Russia, China and five EU states. Kosovo's security is still upheld by a large NATO-led force.
ipj/cmk (AFP, AP, Reuters)