A Serbian police officer was killed and another wounded in a shootout on Thursday during a routine vehicle check near the Bosnian border, the government said, blaming neighboring Kosovo for an act of "terrorism."
Kosovo said the incident should not be politicized.
The two Balkan nations have fractious ties, punctuated by occasional flare-ups of violence, with Serbia refusing to recognize the independence of its former province.
A statement from Serbian Interior Minister Ivica Dacic said police stopped a Serbian-licensed car carrying two people, one of whom got out and shot one officer in the chest with a pistol and another in the shoulder, before escaping.
One of the policemen died and the other is stable in hospital, the statement said, adding that investigators found at the scene a Kosovo passport with the name Artan Hajrizi, and a German identification card.
"He killed a policeman, he carried out this obvious act of terrorism that originates from Kosovo (and) from Albanian structures. This cannot be a coincidence," Dacic told reporters.
Kosovo's people are majority Albanian ethnicity.
Dacic later on Thursday said Bosnian authorities in the town of Bijeljina arrested a man identified only as Z.R. on suspicion of organizing Hajrizi's trip from the southern Serbian town of Presevo to Loznica.
In a brief interview carried by Pristina's Insajderi news portal, a man identifying himself as Artan Hajrizi speaking from Germany said his brother Faton Hajrizi had stolen his documents. Kosovo media reports said Faton Hajrizi had escaped from a jail in Kosovo earlier this month.
Kosovo PM's statement
"We think that this thing should not be politicized, but treated from the security aspect, as well as from the professional and legal angle," Kosovo's Prime Minister Albin Kurti told reporters.
Kosovo's Foreign Ministry advised its nationals to exercise caution in Serbia and to avoid the area of the shootout. Police deployed drones and a helicopter to hunt for the suspect.
The other person in the car, possibly the driver, was arrested at the scene.