THE HAGUE - Radovan Karadzic led a genocidal campaign to make Bosnian Muslims disappear from the face of the earth and carve out a mono-ethnic state for Bosnian Serbs, war crimes prosecutors told a U.N. tribunal on Tuesday.

In opening statements, prosecutors painted a picture of the former Bosnian Serb leader as a supreme commander single-mindedly pursing a campaign of ethnic cleansing during the 1992-95 Bosnian war that killed an estimated 100,000 people.

They spoke to empty chairs on the defendant's side of the court as Karadzic, who denies all the charges, boycotted the trial at the International Criminal Tribunal for the former Yugoslavia for a second day.

The Supreme Commander explained in October 1991 what was coming for Sarajevo: 'Sarajevo will be a black cauldron where Muslims will die. They will disappear, that people will disappear from the face of the earth', senior prosecutor Alan Tieger cited Karadzic as saying in an intercepted call.

He was referring to the 43-month siege of Sarajevo that began in 1992 and killed an estimated 10,000 people as the former Yugoslavia was torn apart in the 1990s by Serbs, Croats and Muslims fighting for land.

The supreme commander had directed his forces in a campaign to carve out a mono-ethnic state within his multi-ethnic country, Tieger said.

This case, your honors, is about that supreme commander. A man who harnessed the forces of nationalism, hatred and fear to implement his vision of an ethnically separated Bosnia -- Radovan Karadzic.

In addition to maps, slides and intercepted phone calls, Tieger showed several videos of Serbian snipers shooting Sarejevo citizens, as well as others of Karadzic on the hills overlooking the city, observing and directing the siege.

He promised to provide witnesses and testimony during the trial showing Karadzic's active involvement in Sarejevo and other campaigns to wipe out minorities.

As prosecutors began their case on Tuesday, Biljana Plavsic, Karadzic's successor as Bosnian Serb president, left a Swedish prison and arrived in Belgrade after winning early release from her sentence for committing war crimes.

BATTLE OF WILLS

Karadzic, 64, has denied all 11 war crimes charges against him, including two genocide charges for the massacre of 8,000 Muslim men and boys at Srebrenica and for broader atrocities.

Karadzic, a psychiatrist before becoming president of the self-proclaimed Republica Srpska, stepped down from power in 1996 and went into hiding until he was captured in July 2008, disguised as an alternative healer in Belgrade.

Karadzic had battled judges during pre-trial proceedings, seeking immunity and more time to prepare, which was denied as judges pressed forward with plans to begin the trial.

Karadzic is the court's highest profile defendant since the trial of ex-Yugoslav President Slobodan Milosevic, whose trial ended with his death in 2006. Milosevic also obstructed proceedings to buy time and gain concessions from the court.

Judge O-Gon Kwon warned Karadzic to appear in court or risk having counsel assigned to him and being tried in absentia.

Should the accused persist in his refusal to attend the trial ... the trial will proceed in his absence, and counsel will be assigned, the South Korean judge said.

Following the end of opening remarks next Monday, a hearing will be held on Tuesday to decide how to proceed if Karadzic continues his boycott. Options include trial in absentia, assigning counsel, seeking outside advice and adjourning to allow assigned legal counsel time to prepare.

If we get enough time to prepare a proper defense, he will appear in court, definitely, said Marko Sladojevic, one of Karadzic's legal advisers, adding that Karadzic was following proceedings closely, working until 5 a.m. on the trial.

A mother who lost much of her family in Srebrenica condemned his absence.

Today again the war criminal Karadzic did not appear at his trial, Nirmela Kolenovic said. For me it means he is a coward and he has acted in a cowardly manner toward the Serbian people.

The complex trial is expected to last until at least 2012 and involve hundreds of witnesses. There are more than 1 million pages of prosecution documents.

(Additional reporting by Aaron Gray-Block; Editing by Michael Roddy)