LJUBLJANA, Slovenia, Sept. 1 -- Talks on the future of Kosovo, the mostly Albanian-inhabited southern province of Serbia, appeared further complicated this week as their main mediator, the veteran Finnish politician Martti Ahtisaari, was accused by Serbs of bias against them.
In recent days, and with increasing vehemence, Serbian officials have questioned the impartiality of Mr. Ahtisaari, a former Finnish president, because of his comments last month that Serbia needed to take into account the legacy of its late leader, Slobodan Milosevic, while negotiating Kosovo's final status.
Mr. Ahtisaari's remarks, made during negotiations in Vienna, were interpreted by the Serbian negotiating team as a suggestion that the Serbian nation was guilty for crimes committed during the Milosevic era, despite statements to the contrary by Mr. Ahtisaari and United Nations officials.
The Finnish mediator, whose formal title is United Nations special envoy for Kosovo, has led the talks since they began in February. He previously helped peace negotiations in Northern Ireland and in the Aceh region of Indonesia.
The current talks are to determine whether Kosovo should become an independent state, as demanded by its Albanian majority, or remain a part of Serbia, as demanded by the Serbian government and the province's small Serbian community. Kosovo has been administered by the United Nations since 1999, after NATO carried out airstrikes against Serbian forces to end their suppression of Kosovo Albanians.
Many senior Serbian politicians said the remarks attributed to Mr. Ahtisaari indicated that he favored independence for Kosovo.
''In the period that lies ahead, we will certainly clear up the full meaning of Martti Ahtisaari's argument that Serbs are guilty as a nation and that this gives grounds for Kosovo's independence,'' Serbia's prime minister, Vojislav Kostunica, said Tuesday, according to Fonet, a private Serbian news agency.
Mr. Ahtisaari's remarks were made on Aug. 8 during a round of negotiations in Vienna, but they appear to have had a delayed impact. It is only in the last week that criticism of his role has mounted.
On Wednesday, Hua Jiang, a spokeswoman for the United Nations office organizing the talks, tried to dispel the controversy.
''The remarks in question were misrepresented and taken out of context,'' Ms. Hua said. ''The special envoy never referred to 'the collective guilt' of the Serbia nation. He noted, in response to a remark by a member of the Serbian delegation on Aug. 8, that every nation had its own burden to bear and had to live and deal with its past.''
Last Friday, Mr. Ahtisaari sought to clarify his comments, saying that the current government in Belgrade could not be held responsible for the actions of the Milosevic government, but that it had to come to terms with its record.
''The historic legacy cannot simply be ignored, but must be taken into account in a search for a solution of the status question,'' he said.
The controversy comes at a time when Serbia appears increasingly unlikely to prevent the international community from granting Kosovo independence. Western countries that support the talks have accused the Serbs of intransigence, and most diplomats say they expect a solution to be imposed this year.
One Serbian analyst, Dusan Janjic, coordinator of the Forum for Ethnic Relations, a nongovernmental organization, said the Serbian politicians, unable to criticize the Western countries, were now attacking Mr. Ahtisaari to show voters that they were defending Serbian national interests.