Mr Slobodan Milosevic has cross-examined the first witness in his war crimes trial.
He sought to discredit a Kosovo Albanian politician who said the Yugoslav government imposed a form of apartheid in the Serbian province.
At times sarcastic and patronising, Mr Milosevic read from a stack of handwritten notes as he vigorously questioned the former head of the Communist Party in Kosovo, Mr Mahmut Bakalli.
Mr Bakalli said a parallel, underground education system was set up in Kosovo to reintroduce classes on Albanian history, culture and language: "The parallel provincial system of schools was set up because of apartheid".
Mr Milosevic asked Mr Bakalli, a university professor, to explain the meaning of apartheid and then recommended he read the UN definition of the word "before he use it again".
Mr Milosevic also confronted Mr Bakalli on his testimony on Monday in which he said Mr Milosevic had known of the 1998 killing of 40 members of the Jashari family in early 1998.
Describing one of his meetings with Mr Milosevic in 1998, Mr Bakalli had said: "I told him: 'You are killing women and children,'" referring to the police action against the Jasharis in the village of Prekaz. "He knew about the incident".
Mr Milosevic asked the witness: "Did you know that they did not want to surrender and they shot at policemen? Do you know that the ones that came out did not get killed? Do you know of any police that would flee when they are fired at from a barricaded position?"
Mr Bakalli said he did not have details of the killing but that he knew women and children were among the victims.
He has accused Mr Milosevic of responsibility for the deaths of "12,000 people, women and children, pregnant women, claiming you were fighting terrorism". His figures of Kosovo casualties were far higher than commonly estimated.
PA