Nikolic personally apologized Thursday for the massacre of Muslim men and boys in Srebrenica in July 1995.

"I kneel and ask for forgiveness for Serbia for the crime committed in Srebrenica," Nikolic said in an interview due to be aired on Bosnian national television on May 7.

The president told BHRT television, however, that "genocide needs to be proved."

Only the trailer of the interview was made available on Thursday.

Bosnian Serbs, who were backed by Belgrade, entered the UN-protected Muslim enclave of Srebrenica in July 1995.

Soldiers separated able-bodied men from the rest of the residents and killed about 8,000. Women, children and the elderly were deported.

The UN International Court of Justice ruled in a 2007 verdict that the killings were genocide carried out by the Bosnian Serb army.

Nikolic, a former far-right nationalist who won Serbia's presidential election a year ago, repeatedly challenged the ruling after taking office.

Bosnian Serb wartime political and military leaders Radovan Karadzic and Ratko Mladic are currently on trial on genocide charges before The Hague-based UN International Criminal Court for the former Yugoslavia (ICTY) for their role in the Srebrenica massacre.

ccp/ipj (AFP, dpa)