BRUSSELS/BELGRADE (Reuters) -The European Union on Monday warned of "escalation and violence" after emergency talks between Kosovo and Serbia failed to resolve their long-running dispute over car licence plates used by the ethnic Serb minority in Kosovo.

After many hours of discussion ... the two parties did not agree to a solution today," EU foreign policy chief Josep Borrell said in a statement to the media.

"I think that there is an important responsibility on the sides of both leaders for the failure of the talks today and for any escalation and violence that might occur on the ground in the following days."

Borrell later discussed the matter with NATO Secretary-General Jens Stoltenberg, who said in a tweet that the NATO-led peacekeeping force in Kosovo was "vigilant".

"Now is the time for responsibility & pragmatic solutions. Escalation must be avoided," he said.

Late on Monday, KFOR Commander Angelo Michele Ristuccia appealed to all parties to avoid any actions that could exacerbate the situation.

A KFOR spokesperson said the major general had met with Kosovo's Interior Minister Xhelal Svecla and stressed the importance of avoiding escalation.

Around 3,700 NATO peacekeepers are still stationed in the former Serbian province to prevent violence between ethnic Albanians and Serbs.