The Serbian and Kosovar prime ministers, Ivica Dacic and Hashim Thaci, are holding another round of EU-brokered talks in Brussels aimed at normalizing relations between Belgrade and Pristina.
The meeting is the eighth round of talks between Belgrade and Pristina since October.
Thaci, heading into the talks, underlined the importance of the meeting.
"Today is a historic day. It is a decisive moment for Kosovo and for the region," he said. "I am a leader [who makes] decisions and today I am here to [make] a decision for my country and the future of my country and the EU perspective of the region. "
In a sign the two sides may be nearing an agreement, Serbia's powerful Deputy Prime Minister Aleksandar Vucic has joined the talks.
Vucic leads the Serbian Progressive Party (SNS), which is the largest in parliament.
Speaking at a press conference in Belgrade on April 1, Serbian President Tomislav Nikolic cautioned that a final agreement might not be reached.
"Intractable statements from Pristina put us before a fait accompli and are not encouraging," he said. "We are not sending a delegation [to Brussels] to request, by ultimatum, the fulfilment of the Serbian Constitution and laws, but neither are we sending a delegation to agree on nothing [for Kosovar Serbs]."
Serbia refuses to recognize the independence declared in 2008 by Kosovo, which has an ethnic Albanian majority.
The key issue in the talks is the future of ethnic Serbs who are in the majority in northern Kosovo.
Belgrade wants a high level of self-rule for Kosovo's Serbs, including their own police and judicial authorities.
Pristina has rejected this as a de facto partition of Kosovo.
On April 1, Vucic suggested the "frozen conflict" could not be allowed to drag on indefinitely.
"The agreement must be reached," he said. "Serbia cannot wait another year or five years over this frozen conflict. Who will wait? People don't have any patience left. A little hope was shown to them, a small light at the end of the tunnel, and now to tell them that we are going to continue with this frozen conflict, or no we don't want to go toward the [European] world or tell them that we don't want anything, we don't need anybody, we can be on our own. We can't, we can't. Yes, we have to protect our national interests, but we must also know the limits."
Thaci on April 1 urged Serbia to accept a deal that would give Serbs in Kosovo's north more rights but which falls short of giving them autonomy.
The EU's foreign affairs chief, Catherine Ashton, who is mediating the talks, said in a statement on April 1 that she believed an agreement was within reach, "even if it won't be easy."
Nikolic warned that failure to reach a deal would mean "economic hardship" for Serbia and delay the start of accession talks with the European Union.
The European Commission is to deliver a report in two weeks on progress made by Belgrade and Pristina on normalizing relations.
With reporting by AP, AFP, and B92