Mr Karadzic is accused of orchestrating a campaign of "ethnic cleansing"
Ex-Bosnian Serb leader Radovan Karadzic has dismissed as myths the alleged two worst atrocities of the 1992-95 Bosnian war and denied his involvement.
Mr Karadzic told his trial at The Hague that Sarajevo, where some 12,000 people died in 44 months, was "not a city under siege" by Bosnian Serb forces.
He said claims of the 1995 Srebrenica massacre of more than 7,000 Muslim men and boys were based on "false myths".
He is accused of genocide and war crimes committed during the conflict.
The 64-year-old insists he is innocent of all 11 charges.
He should be given the Nobel Prize for lying
Sabra Kolenovic, Mothers of Srebrenica
On Tuesday, the trial was adjourned, pending a decision on Mr Karadzic's appeal for it to be delayed until June on the grounds that he needed more time to prepare to defend himself.
Last week, the trial chamber rejected his first request and had planned to start hearing prosecution witnesses on Wednesday.
On Monday, during the first day of trial, Mr Karadzic described the conflict as "just and holy", blaming Bosniaks (Bosnian Muslims) for starting it.
On the second day of his opening statement at the International Criminal Tribunal for the former Yugoslavia (ICTY), Mr Karadzic said that Sarajevo was "not a city under siege, it was a city divided".
Eleven counts of genocide, war crimes, crimes against humanity and other atrocities
Charged over shelling of Sarajevo during the city's siege, in which some 12,000 civilians died
Allegedly organised the massacre of up to 8,000 Bosniak men and youths in Srebrenica
Targeted Bosniak and Croat political leaders, intellectuals and professionals
Unlawfully deported and transferred civilians because of national or religious identity
Destroyed homes, businesses and sacred sites
He said that Bosnian Serb gunfire and shelling of Bosnia's capital was restricted to legitimate targets.
And he accused Bosniaks and Croats of turning the city's kindergartens, schools and hospitals into military facilities by setting up command posts and sniper positions there.
"We can prove that they [Bosnian Serb enemies] did shell their own people and killed all their own people," Mr Karadzic said.
He said Bosniaks and Croats had used terror attacks in Sarajevo in an attempt to bring Nato and Western countries and troops on their side.
The 44-month siege of Sarajevo ended in November 1995.
Referring to Srebrenica, Mr Karadzic said claims that Bosnian Serb troops committed a massacre there in July 1995 were based on "false myths and false victims".
He added: "It is going to be easy from me to prove that I had nothing to do with it."
Earlier on Tuesday, Mr Karadzic said he had been seeking to defend Bosnian Serbs from "state-sponsored terrorism" and had tried to prevent the war.
Reaction from some of the survivors of the Srebrenica massacre, who were in The Hague to attend proceedings, was indignant.
"He should be given the Nobel Prize for lying," Sabra Kolenovic of the Mothers of Srebrenica was quoted as saying by Reuters.
Correspondents say Mr Karadzic is trying to show that there was no joint criminal enterprise to carry out the genocide or "ethnic cleansing", but that Serbs were only defending themselves from perceived Muslim aggression.
Mr Karadzic faces two charges of genocide, as well as nine other counts including murder, extermination, persecution and forced deportation.
More than 100,000 people were killed during the 1992-95 Bosnian war
Prosecutors say he orchestrated a campaign of "ethnic cleansing" against Muslims and Croats in eastern Bosnia to create an ethnically pure Serbian state.
In his opening statement last October, prosecutor Alan Tieger said Mr Karadzic had "harnessed the forces of nationalism, hatred and fear to pursue his vision of an ethnically segregated Bosnia".
Mr Karadzic had boycotted earlier proceedings, insisting on more time to prepare his case.
In November, the court appointed British lawyer Richard Harvey to take over the defence if he continued his boycott.
Mr Karadzic was arrested in Belgrade in 2008 after nearly 13 years on the run.
During his time in power, he was president of the self-styled Bosnian Serb Republic and commander of its army during the Bosnian conflict which left more than 100,000 people dead.
He is the most significant figure to face justice at this tribunal since the former Yugoslav President, Slobodan Milosevic, who died of a heart attack in 2006 before his own trial was concluded.