Bosnian Serb commander General Ratko Mladic defiant at genocide trial in The Hague

Ratko Mladic was a shadow of the swaggering general who once "held Sarajevo in the palm of his hand" during Bosnia's 1992-95 war as his long-awaited genocide trial opened - but he still managed to inflame Bosnia's festering war wounds with the flick of his hand.

Hobbled by strokes and wearing a business suit instead of combat fatigues, the frail 70-year-old gestured towards the families of massacre victims in an angry exchange of hand signals through the bulletproof glass that separated them.

"Not even an animal would behave like that," said Mevlija Malic as she watched the trial on television in Bosnia.

Mladic is accused of commanding Bosnian Serb troops who opened the war with a campaign of murder and persecution to drive Muslims and Croats out of territory they considered part of Serbia. His troops rained shells and snipers' bullets down on civilians in the 44-month-long siege of the Bosnian capital, Sarajevo, and butchered 8,000 Muslim men and boys in Srebrenica in July 2005, Europe's worst massacre since the Second World War.

"The world watched in disbelief that in neighbourhoods and villages within Europe a genocide appeared to be in progress," prosecutor Dermot Groome said at the UN court in The Hague.

Twenty years after the war that left 100,000 dead, Bosnia remains divided into two mini-states - one for Serbs, the other shared by Bosnian Muslims and Croats - linked by a central government.

Mladic fled into hiding after the war and spent 15 years as a fugitive before international pressure on Serbia led to his arrest last year. Now he is held in a one-man cell in a special international wing of a Dutch jail and receives food and medical care that would probably be the envy of many in Bosnia.

But the fact that he is jailed and on trial is another victory for international justice and hailed by observers as evidence that war crimes tribunals more often than not get their indicted suspects, even if they have to wait years. In another court in The Hague today, former Liberian president Charles Taylor faced a sentencing hearing after being convicted last month of aiding rebels in neighbouring Sierra Leone's civil war.

That is heartening news for the International Criminal Court, which has indicted the likes of Sudanese president Omar al-Bashir for genocide but appears nowhere close to having him arrested.

In a demonstration of Bosnia's continuing ethnic divide, people who gathered in the Serb stronghold of Pale to watch the trial on television applauded as they saw the ex-general enter the courtroom.

"Mladic is our hero, it's sad that we see him there," said Milan Ivanovic, a 20-year-old law student.

Prosecutor Mr Groome told the three-judge panel that Mladic was hand-picked by Bosnian Serb leader Radovan Karadzic because of his skills as a military commander but also "because Karadzic believed he was willing to commit the crimes needed to achieve the strategic goals of the Bosnian Serb leadership".

Mr Groome signalled that prosecutors would use Mladic's own words against him in the trial, drawing on a stash of wartime diaries Mladic kept, radio intercepts and appearances he made on television during the war.

In one such TV appearance, Mladic showed a news team around the Serb artillery dug into hills overlooking Sarajevo and denied any involvement in war crimes - foreshadowing his defence now that his actions were intended only to protect Serbs.

"I did not take part in any crimes. I have only defended my people," Mladic said. He has refused to enter pleas to the 11 charges against him in The Hague but denies wrongdoing.

However in another video he is heard boasting, "whenever I come by Sarajevo, I kill someone in passing ... I go kick the hell out of the Turks" - a denigrating reference to Bosnian Muslims.

"(Mladic) held Sarajevo in the palm of his hand," Mr Groome said, playing an intercepted radio communication of Mladic ordering the shelling of part of the city and a video of civilians scurrying across devastated streets to avoid sniper fire during Sarajevo's siege.

Mr Groome said all the attacks were part of an "overarching" plan hatched by Karadzic and former Yugoslav president Slobodan Milosevic to ethnically cleanse large parts of Bosnia of non-Serbs and carve out a "Greater Serbia" from the ruins of the former Yugoslavia.

Karadzic is also on trial at the tribunal following his 2008 arrest. Milosevic was put on trial here, too, for fomenting wars across the Balkans, but he died of a heart attack in 2006 before judges could deliver their verdict.

Prosecutors say they will use evidence against Mladic from more than 400 witnesses, though very few of them will testify in court. Much of their evidence has already been heard in other cases and will be admitted as written statements.

The first witness is to start testifying on May 29, but Presiding Judge Alphons Orie of the Netherlands hinted that he may postpone the case because prosecutors have not disclosed all evidence to Mladic's defence.

Bosnia's president hailed the trial's opening as a historic day in the still bitterly divided country's recovery from its war wounds.

"First of all we are expecting from this trial the truth," said Bakir Izetbegovic. "The truth and then justice for the victims, for the families of the victims. It is the worst period of our history."

Mladic gave a thumbs-up and clapped towards the court's public gallery as the trial got under way. He occasionally wrote notes and showed no emotion as prosecutors outlined his alleged crimes.

One woman in the public gallery called him a "vulture".

After a break in proceedings, Judge Orie rebuked Mladic and the public about "inappropriate interactions" and said he might shield Mladic behind a screen if the outbursts continued.

Munira Subasic, who lost 22 relatives in the Srebrenica massacre, claimed that Mladic made a throat-slitting gesture towards her after she had held up both her hands, wrists crossed to indicate Mladic was in captivity. Mladic's lawyer Branko Lukic did not confirm her version of events, but claimed that somebody in the audience raised their middle finger at Mladic.

"He is very easily provoked and we had that gallery full of people very ready to provoke," Mr Lukic said.

In Srebrenica, widows and mothers of the massacre victims gathered to watch the trial together and reacted with outrage to Mladic's apparent lack of emotion.

"This is so painful for us. It really hurts. We did not lose some chicken. We lost our sons," said Suhreta Malic, whose children and more than 30 other family members were killed in the massacre.

Crying, she sat in front of the TV with photographs of her dead children in her hands.