THE HAGUE, Oct 2, 2008 (AFP) - Ex-Yugoslav army chief Momcilo Perisic went on trial for war crimes Thursday charged with a civilian attack once described as 'a bloody criminal bombardment' by his political boss Slobodan Milosevic.

The most senior Yugoslav army officer to be prosecuted for war crimes committed in the 1990s Balkans conflict, Perisic has pleaded not guilty to 13 counts before the International Criminal Tribunal for the former Yugoslavia.

But prosecutor Mark Harmon insisted in The Hague-based court Thursday that Perisic should be held responsible for the deaths of thousands of people during a 44-month siege of the Bosnian capital Sarajevo that ended in November 1995.

'General Perisic was fully appraised of the situation in Sarajevo,' he told the three judges. 'He was aware that his subordinates had committed crimes.'

Perisic, 64, has been charged with murder, persecution, extermination, inhumane acts and attacks on civilians -- all committed against non-Serbs in Bosnia and Croatia.

As chief of the general staff of the Yugoslav army from August 1993 to November 1998, he had served under Yugoslav president Slobodan Milosevic whose own war crimes trial was cut short after four years when he died in March 2006.

Harmon told the court that Milosevic, upon hearing of the shelling of civilians in Sarajevo, had described it as 'a bloody criminal bombardment'.

Perisic also stands accused over the 1995 massacre of some 8,000 Muslim men and boys in the Bosnian town of Srebrenica; and of cluster bomb attacks on the Croatian capital Zagreb in May 1995 in which seven civilians died and at least 194 were wounded.

Harmon argued that Perisic had been a staunch supporter of Milosevic's vision of a single Serbian state and one of his 'principal collaborators'.

'He faithfully and without reservation implemented the policies of the FRY (Former Yugoslav Republic),' the prosecutor told a panel of three judges.

'General Perisic issued orders and commands. He provided extensive military aid to the VRS (Serb army in Bosnia), which had a substantial effect on the commission of the crimes.

'He consistently failed in his duty to investigate and punish crimes committed by his officers ... of which he was fully aware. He created an environment of impunity wherein his subordinates were encouraged and did persist to commit crimes knowing there would be no consequences.'

As for the Srebrenica massacre, which has been termed genocide by the tribunal, Harmon said Perisic had been warned that crimes against the Muslim population were likely to occur.

'General Perisic was aware that Muslims in Bosnia were at considerable risk and that a Bosnian Serb takeover of the safe area would result in the substantial likelihood of Muslims being forcefully transferred and killed.'

Several of Perisic's former subordinates have already been convicted by the tribunal, but Bosnian Serb general Ratko Mladic has been on the run since being indicted 13 years ago over the Srebrenica massacre and other crimes.

Defence lawyers are expected to present an overview of Perisic's case to the court on Friday.