Bosnian Serb leader Dragan Cavic has protested to the European Union's peacekeeping force after the wife of a war crimes suspect was shot dead.
Eufor says its troops returned fire after they were shot at
Rada Abazovic, 46, was killed in an exchange of fire with Eufor troops, who arrested her husband Dragomir Abazovic.
Their son was also injured and Mr Abazovic was reported to have suffered self-inflicted head wounds.
In a letter, Mr Cavic said nobody had a mandate to kill in Bosnia and described the shooting as a brutal show of force.
He urged the Italian commander of Eufor to investigate the arrest operation in Rogatica, in eastern Bosnia, on Thursday.
"This is a black mark for Eufor and will destroy confidence in the force completely," Mr Cavic said.
"It is tragic that the result of their operation should be the death of the wife of an alleged suspect and injury to his young son."
A Eufor spokesman said the peacekeeping troops were preparing for the operation with the Rogatica local police when they came under fire. The troops then returned fire, he said.
Mr Abazovic is wanted by Bosnia-Hercegovina's war crimes court for offences he is alleged to have committed in the 1990s around Rogatica.
He is not on the list of suspects wanted by the United Nations International Criminal Tribunal for the Former Yugoslavia.
The 6,300-strong Eufor took over peacekeeping in Bosnia from a Nato force in 2004 and has been involved in searching for war crimes suspects and combating organised crime.