Bosnian Serb ex-military chief Ratko Mladic was faced with a survivor of a 1992 mass execution today as war crimes prosecutors opened their case against the so-called "Butcher of Bosnia".

Elvedin Pasic told international judges sitting in The Hague of his idyllic childhood before the onset of the brutal ethnic conflict.

During the course of his testimony before the International Criminal Tribunal for the former Yugoslavia, Mr Pasic is expected to detail a systematic programme of persecution leading to mass killings.

"Before the war we had a great time," Pasic, who as a 14-year-old boy lived in the village of Hvracani in northern Bosnia, told the court.

"We were playing basketball and football, we used to do everything together. Muslim, Croats and Serbs, we were all having a great time, respecting each other."

Things began to change in the spring of 1992, when Mr Pasic first noticed a convoy of military vehicles with soldiers in the uniform of the Yugoslav national army, giving Muslims the three-fingered Serbian salute.

Mr Pasic is expected to "describe the destruction and damage to residential property, attacks on villages (and) the persecution of non-Serbs," prosecutors said in a witness list before the court.

Having previously testified in other trials, Mr Pasic will recall how he was separated from other men in his family and consequently "survived the execution of around 150 persons in November 1992 in the village of Grabovica," in northern Bosnia.

Mladic, 70, has been indicted by the ICTY on 11 counts of genocide, war crimes and crimes against humanity for his role in the Balkan country's war.

The trial of the man dubbed the "Butcher of Bosnia" was abruptly suspended on 17 May, only a day after it opened in The Hague, because of prosecution irregularities.

Mladic faces charges relating to the massacre in the enclave of Srebrenica in northeastern Bosnia in 1995, when almost 8,000 Muslim men and boys were murdered by Bosnian Serb troops under Mladic's command.

He also faces charges for the terrorising of the capital Sarajevo during 44 months of shelling and sniping which killed 10,000 people.

Prosecutors also hold him responsible for taking some 200 UN peacekeepers hostage and for allegedly ordering his troops to "cleanse" Bosnian towns, driving out Croats, Muslims and other non-Serb residents.

At the same time that the prosecution was beginning, thousands lined the streets of Sarajevo to pay their respects to the remains of 520 victims of the Srebrenica massacre who will be buried on the 17th anniversary of the atrocity.

Three trucks loaded with 520 coffins passed through Sarajevo on their way to the Potocari cemetery near Srebrenica where they will be buried on Wednesday.

"Our children are returning to where they left from in 1995. Unfortunately they are not alive," Munira Subasic, who heads an organisation of women of Srebrenica whose husbands and sons were killed, told AFP as she watched the vehicles.

Mladic was arrested in northeastern Serbia last year after some 16 years on the run and subsequently moved to The Hague. He has pleaded not guilty to the charges. If found guilty he could face life in prison.

Mr Pasic will be followed in the witness stand by UN advisor David Harland, who will describe the siege of Sarajevo, where 1,000 shells landed on average each day between 1993 and 1995, with the exception of lulls during a 1994 ceasefire.

Also among the first witnesses to testify will be Eelco Koster, one of the some 450 Dutch UN peacekeepers guarding the "protected" enclave at Srebrenica when it was overrun by Mladic's forces.

Former Bosnian Serb political leader Radovan Karadzic is also on trial before the ICTY, with both men accused of being the masterminds of a criminal plan to rid multi-ethnic Bosnia of Croats and Muslims.

Mladic's one-time mentor, former Serbian president Slobodan Milosevic died in The Hague four years into his own genocide trial in 2006.