A Bosnian Serb war crimes suspect has been handed to the international war crimes tribunal in The Hague following extradition from Argentina.
Lukic was sentenced to 20 years in absentia by a Belgrade court
Milan Lukic, 38, was arrested in Buenos Aires last August after being on the run for more than seven years.
The indictment says he led a group of paramilitaries called the "Avengers" in the 1992-95 Bosnian War and lists 21 charges including murder.
Lukic is expected to enter a plea before a UN judge later this week.
Each of Lukic's war crimes charges carries a maximum punishment of life imprisonment.
The indictment lists 86 alleged victims, from just two days old to 75 years.
Lukic was indicted by the tribunal in 1998 at the same time as his cousin, Sredoje, who is also awaiting trial.
Milan Lukic's UN indictment accuses him of forming the Avengers paramilitary group - also known as the "White Eagles" - in 1992. It says they worked with local police and military units to exact a "reign of terror" against Bosnian Muslims in the Bosnian city of Visegrad.
It documents two cases in which Lukic barricaded people in buildings before setting fire to them, killing at least 140 people.
Lukic is also wanted in Serbia, where he was sentenced in absentia to 20 years in prison for war crimes.
In 2003, a court in Belgrade found him and three other men guilty of torturing and murdering 16 Muslim civilians whom they abducted from a bus travelling from Serbia to Bosnia in 1992.
Serbian officials say Lukic's paramilitary group was responsible for abducting, torturing and killing the victims - all nationals from the republics that constituted the former Yugoslavia - before throwing them into a river.
The incident - known as the Sjeverin case after the town where the victims were kidnapped - was the most serious crime to take place on Serbian territory during the Balkan wars in the early 1990s.