Three other mission members were wounded in fire opened at two EULEX vehicles with six persons around 7.30 am, according to unofficial reports.
The Croatian ministry confirmed that a Croatian EULEX member was in one of the vehicles, but not in the one with the wounded EULEX members.
The incident in the north of Kosovo, mainly populated by Serbs, happened in the run-up to local elections in Kosovo set for November 3. Serbia's officials have called on Kosovo Serbs to take part in the polls on several occasions.
Serbia's Prime Minister Ivica Dacic deplored the murder of the EULEX member, branding the attack as an extremist act which damaged Serbia's reputation.