The aim was to get Kosovo and Serbia on the road to resolving their differences. But the presidents have abruptly called off a face to face meeting in Brussels,
Quashing hopes of a deal over a land swap, which could help both Kosovo and Serbia move towards EU membership.
"We are not talking about partition or new borders. For me its a little bit risky," Behgjet Pacolli, Foreign Minister of Kosovo, told reporters, adding: "It's not on the table."
The talks had been brokered by the EU's foreign policy chief Federica Mogherini.
The failure for the two presidents to meet in person is a sign of a backlash in both Kosovo and Serbia to the land swap proposal.
Mogherini has admitted "difficulties remain."