The United Nations tribunal on war crimes in the former Yugoslavia has named the Bosnian Serb leader, Radovan Karadzic, and his army commander, General Ratko Mladic, as suspects in an investigation into genocide, torture and "ethnic cleansing" in Bosnia.
The move came despite pleas for a postponement from UN officials fearful of a detrimental effect on negotiations with the Serbs on extending the Bosnian truce which expires on 1 May.
"My office is investigating the question of responsibility of these prominent individuals for genocide, murder, rape, torture and the forced removal of many thousands of civilians from large parts of Bosnia and Herzegovina, including events ... in Prijedor and Bosanski Samac," Justice Richard Goldstone, the chief prosecutor, said in The Hague yesterday.
His announcement came as Dusan Tadic, the only suspect in custody, was extradited from Munich to stand trial in The Hague. Mr Tadic is accused of killing at least 32 people and torturing 61 more at the Omarska prison camp near Prijedor in north-western Bosnia, site of some of the worst examples of "ethnic cleansing".
He is due to appear this summer at the first such trial since the Second World War. Bosanski Samac is alleged to have housed a rape camp.
Mr Goldstone wants the tribunal to ask that the Bosnian government suspend its own proceedings against the two Bosnian Serb leaders and Mico Stanisic, former head of the security police, and turn over any evidence to the international prosecutor.
"The deferral applications reflect my strategy, which is to indict those in leadership positions, both civilian and military, who are responsible for serious violations of international law," Mr Goldstone said. The trial chambers of the tribunal will meet on 9 May to consider his request, to which the Bosnian government has already agreed.
The head of the state's war crimes commission, Mirsad Tokaca, greeted the news with delight. "Our request that the first to be prosecuted be those who organised and inspired these crimes - the ideologists and those who issued orders - has been fulfilled," he said.
The chief prosecutor's investigations will also address the siege of Sarajevo and attacks on aid convoys and UN peace-keepers. Mr Goldstone said the process was at an advanced stage, and formal charges could follow by the end of the year. He has also extended the investigation to non- Serbs for the first time, considering allegations of massacres and "cleansing" of Muslims by Croats in the Lasva valley, central Bosnia.
So far the tribunal has indicted 22 Serbs, including Zeljko Meakic, the commander of the Omarska camp who is charged with genocide, but 21 remain at large.
The case against Mr Tadic, and the investigations into the leadership, cover what the Bosnian government and human rights activists describe as a systematic campaign to exterminate or expel Muslims living in what are now Serb-held lands during the summer of 1992 and beyond. Mr Tadic, now living at Scheveningen prison near The Hague, is expected to plead not guilty to charges that he murdered, raped and tortured Muslims and Croats in Omarska.
Mr Goldstone's report on the beating to death of three prisoners includes graphic details: "Tadic then forced a fourth prisoner to drink motor oil from the garage and then bite off the testicles of the unconscious prisoners," he wrote. Mr Karadzic and General Mladic are accused of sanctioning such crimes.
Before the war, some 355,000 Muslims lived in the Banja Luka area; only 30,000 remain. And, according to the UN High Commissioner for Refugees, 7,000 non-Serbs have been expelled from Banja Luka since October 1994. A further 200,000 people are thought to have died or disappeared in the war.
There was no official response from the Serb leadership, which has never recognised the tribunal's authority.
Diplomats and UN officials questioned the timing of Mr Goldstone's announcement, which came one week before the expiry of a four-month truce in Bosnia.
Officials said the UN tried in vain to persuade Mr Goldstone to delay the process for a few months, or at least until the end of this month. Although the announcement could derail what remains of the peace talks, the UN does not expect Serb reprisals against its staff.
"The reality is we have almost no freedom of movement across Serb-controlled territory and the airport is essentially closed, so their points of leverage are relatively few, since they've already cut us off," a UN source said.