But European diplomats, speaking on the condition of anonymity because they are not authorized to discuss the subject for attribution, expressed worries that Kosovo’s Serbs could provoke ethnic Albanians, undermining whatever collective Serbian and Albanian authority remained in northern Kosovo, and entrenching Serbian control so that de facto partition became a political reality.

Image Cabra was also the scene of ethnic tensions in 2004. Credit... The New York Times

“The Serbs appear intent on provoking an Albanian reaction and to make the international community’s mission here impossible, but we will not allow legal partition,” said one senior European Union diplomat.

But another European diplomat said that if Serbs pursued de facto division, “there is not a lot that could be done.”

The political temperature in Cabra, an agricultural village of about 70 ethnic Albanian families, has particular resonance because it was here in March 2004 that three ethnic Albanian boys drowned under mysterious circumstances, prompting Albanians to riot across Kosovo.

As the Serb protesters gathered on the road outside the village Wednesday, local ethnic Albanians vowed they would stay to ensure that northern Kosovo remained in ethnic Albanian hands. Children wearing T-shirts with Albanian flags gathered to observe the peacekeepers’ tanks parked at the edge of the town.

“This is my land, and we must stay here to show Serbia that this is Kosovo,” said Zuka Ilir, an unemployed 28-year-old. “But we are afraid. We don’t know what will happen.”

Xhevadet Beka, a 26-year-old engineer, added: “I will stay here and fight if I have to. For now we put our faith in NATO, the E.U. and the United States. But we are very, very afraid that the Serbs will try and take over northern Kosovo, and it is impossible. We will not allow it.”