The NATO chief Friday urged "restraint" this weekend when tens of thousands of Kosovo Serbs with dual citizenship vote in the Serbian parliamentary and presidential elections.
"I strongly urge all leaders and all communities to show restraint during the voting process," Secretary General Anders Fogh Rasmussen said ahead of the Sunday ballot.
"In this critical period, it is important to avoid any unilateral actions or statements that can raise tensions," he said, calling on both Pristina and Belgrade "to continue cooperating with the international community in order to ensure a calm and peaceful vote."
The Organisation for Security and Cooperation in Europe, which has been mandated by Belgrade and Pristina to enable Kosovo Serbs holding dual citizenship to vote, said this week that some 110,000 voters in Kosovo would be eligible to cast ballots in the Serbian elections.
NATO has deployed extra troops in Kosovo to prevent unrest in the ethnically tense north ahead of the vote. Its KFOR peacekeeping force currently has some 6,200 soldiers from 29 nations.
"KFOR and EULEX will continue to coordinate closely on the ground," Rasmussen said, referring to EU police. "The future of the whole region is integration in the Euro-Atlantic region, so we must do all we can to avoid any possible setback in the region's progress towards that goal."
Kosovo declared independence from Serbia in 2008 and has been recognised by 90 countries, including the United States and all but five members of the European Union.
Serbia still considers the territory its southern province. The Serb majority in northern Kosovo has announced it would also organise local polls, but both Belgrade and Pristina rejected the plan as unacceptable.