A Nato spokesman, Major Roland Lavoie, said the shootings in the American sector were being investigated, but that the Russians acted under the rules of engagement, which allow peace-keepers to use force to defend themselves.
According to Major Lavoie, the Russians rushed to an area north-east of Gnjilane after a firefight erupted between Serbs and ethnic Albanians near Korminjane village, in which one Albanian died and two others were wounded.
They found Serbs beating two of the wounded Albanians, and ordered them to stop. The Serbs started shooting at the Russians, who returned fire.
Albanians in Kosovo have strongly opposed the presence of Russian soldiers, accusing them of being pro-Serb. Serbs in Kosovo have seen Russian troops as fellow Orthodox Christian Slavic protectors against what the Serbs perceive as the threat from Islamic Albanians. US and Nato commanders have said, however, that Moscow's troops have been even-handed since arriving in Kosovo as part of the K-For peace-keeping force.
The latest deaths could lead to a solution of the stand-off in the southern town of Orahovac, where Albanians have been blocking the main road since 23 August to prevent a Russian K-For battalion arriving.