Ivica Dačić and Hashim Thaci, who head the governments in Belgrade and Priština, are once again meeting in Brussels on Tuesday.
They are discussing the concrete steps to implement the Brussels agreement, which they initialed on April 19.
The two sides set up teams to discuss implementation, which met twice since, but failed to reach any agreement.
EU foreign policy chief Catherine Ashton acts as mediator, and is first holding bilateral meetings with Dačić and Thaci.