Momcilo Krajisnik, 71, was a former key ally of Radovan Karadzic, the Bosnian Serb political leader during the 1990s war who was himself jailed for 40 years for genocide.
Momcilo Krajisnik, 71, was a former key ally of Radovan Karadzic, the Bosnian Serb political leader during the 1990s war who was himself sentenced last year to 40 years in prison for genocide and crimes against humanity.
The goal of the Belgrade meeting was the "protection of the rights of Serbian people in the region," a statement from Nikolic's office said.
The talks also focused on ways to promote cultural ties among Serbs of the former Yugoslavia, it said.
A Belgrade-based human rights group immediately slammed the meeting.
"By meetings of top state officials with convicted war criminals, Serbia's institutions obstruct the process of confronting the causes and consequences of the 1990s wars... and insult victims' dignity," the Humanitarian Law Centre said in a statement.
Krajisnik was arrested in 2000 in the Bosnian Serb wartime stronghold of Pale, just near Sarajevo.
Six years later the International Criminal Tribunal for the former Yugoslavia (ICTY) in The Hague convicted him of persecuting and forcibly expelling non-Serbs and crimes against humanity committed during Bosnia's 1992-1995 war.
His initial 27-year sentence was later cut on appeal to 20 years and in 2013 he was granted early release from a British prison.
Karadzic was sentenced by the ICTY in March to 40 years in jail last year notably for the 1995 Srebrenica massacre of some 8,000 Muslim men and boys.
Bosnia's war between its Croats, Muslims and Serbs claimed some 100,000 lives.
It left the Balkan country split into two semi-autonomous entities -- the Muslim-Croat Federation and the Serbs' Republika Srpska.
Nikolic, a former ally of Serbian ultranationalist Vojislav Seselj, was elected president in 2012 at the head of a centre-right party.
Russia-oriented Nikolic on Monday took part in ceremonies marking the 25th anniversary of the Republika Srpska's creation.