(ANSA) - BELGRADE, 04 GIU - In northern Kosovo, after a night spent calmly and without excesses, groups of Serbs this morning returned to demonstrations in front of the municipalities of Zvecan, Leposavic and Zubin Potok against the election of new Albanian mayors, and to demand the withdrawal of Kosovo's special police from the north and the release of two Serbs arrested in the May 29 clashes in Zvecan. The situation is calm but interethnic tension is still palpable. Some demonstrators remained all night manning municipal buildings, which have been cordoned off for days by metal barriers and barbed-wire fences, with a heavy presence of soldiers from Kfor, the NATO Force in Kosovo, Police units remain inside the municipalities. NATO soldiers also garrison other sensitive points, including access roads to the center of towns and to municipal offices. Meanwhile, from the international community, primarily the EU, U.S., NATO, and OSCE, appeals for calm and calls for the parties to refrain from unilateral actions likely to further fuel tensions continue. Diplomacy is working to defuse the new crisis in the north, and EU and U.S. envoys Miroslav Lajcak and Gabriel Escobar are scheduled to arrive in the region tomorrow for talks with the leaderships in Belgrade and Pristina. The orientation seems to be to go for new local elections in the north, to be held on a regular basis and with the participation of Serbs, whose boycott on April 23 paved the way for the election of ethnic Albanian mayors. Kosovo Prime Minister Albin Kurti for his part has let it be known that a new vote can be held only after the Serb protests have ended. From the EU came at the same time a pressing invitation to the Kosovar leadership to take action toward the creation of the Community/Association of Serb-majority Municipalities of Kosovo. A body envisaged by agreements a decade ago, clamored for by Belgrade but rejected by Pristina as unconstitutional. (ANSA).