John Clint Williamson was named lead prosecutor in an investigation to be carried out by the European Union Rule of Law mission in Kosovo, or EULEX, officials said Tuesday in Pristina.
The probe comes after a report issued by the Council of Europe accused Kosovo Prime Minister Hashim Thaci and other senior figures of being involved in an organ-trafficking network.
The allegations, made by Swiss MP Dick Marty in December, alleged Thaci and other rebel commanders of the Kosovo Liberation Army harvested organs from civilians imprisoned in detention camps during hostilities between Belgrade and the breakaway province in 1999.
The report contended the organs, some which were allegedly taken from ethnic Serbs, were sold on the black market to raise funds for the rebellion.
Marty's report alleged Thaci is the head of an criminal organization and that "numerous indications" of organ harvesting exist.
The prime minister, however, has called the report a fabrication designed to malign Kosovo, the Voice of America reported.
EULEX was set up by the European Union only months after Kosovo declared independence from Serbia, with its declared mission to be helping Kosovo's law enforcement agencies develop sustainability and accountability.
Serbian Foreign Minister Vuk Jeremic, addressing the U.N. Security Council Tuesday, said his country "welcomes EULEX's contribution to uncovering what occurred inside Kosovo itself."
But, he argued, "the harvesting and smuggling of organs of innocent Serbian civilians took place beyond that territory, as the relevant allegations appear to encompass various U.N. member states in Europe, Asia and Africa," and that is beyond the scope of EULEX.
"It is an unassailable fact that the EU's Law and Order Mission in Kosovo has neither the mandate -- nor the temporal and the territorial jurisdiction -- to carry out an investigation that would be comprehensive in scope.
"On its own, it has no ability to ensure the cooperation of all concerned. Only a mechanism created by the Security Council can do that."
Jeremic urged the United Nations to investigate not only the organ-harvesting allegations, but also act against Kosovo for its "unilateral actions" of July, when it sent paramilitary forces to it northern borders with Serbia, sparking protests and at least one death.
"Unilateralism is incompatible with efforts to reach a mutually acceptable solution to the problem of Kosovo," the foreign minister said. "Everyone must choose which road to take. No equivocation is possible."
Williamson, meanwhile, comes to the EULEX task force after serving as the head of Kosovo's Justice Department in 2001-2002 when the territory was under the administration of the United Nations, and also served as U.S. ambassador-at-large for war crimes issues, The Daily Telegraph reported.
Also on his agenda will be allegations Thaci and other 1990s members of the Kosovo Liberation Army are now running a drug-dealing network.
Nothing has been turned up so far in previous organ-harvesting investigations by the United Nations and European Union. But Serbia and Russia have kept up pressure for a full probe, succeeding in bringing the issue to international attention, the newspaper said.
Notable deaths of 2014 [PHOTOS]