UN appeals judges at The Hague have reversed the conviction of a Bosnian Serb army general for complicity in the 1995 Srebrenica genocide.
Vidoje Blagojevic has always denied the charges
Vidoje Blagojevic's jail sentence was reduced from 18 to 15 years. Other related convictions were upheld.
The judges ruled he should have been acquitted because his original trial found he had not known of the massacre and only provided logistical support.
Over 7,000 Muslims died in Srebrenica at the end of the 1992-1995 war.
It is considered to be the worst single atrocity in Europe since World War II and has been legally constituted genocide.
Blagojevic commanded the Bratunac brigade of the Bosnian Serb army at the time.
He was subordinate to Bosnian Serb General Radislav Krstic, who in April 2004 became the first person to be found guilty of aiding and abetting genocide by the International Criminal Tribunal for the former Yugoslavia (ICTY).
The five-judge appeals panel at the ICTY ruled that Col Blagojevic had not been complicit in the genocide at Srebrenica because he had not known his troops intended to commit it.
"On the basis of the foregoing, the appeals chamber... reverses his conviction for complicity in genocide," the presiding judge, Fausto Pocar, said.
Dragan Jokic's appeal was rejected by the ICTY
However, the court upheld Blagojevic's other convictions for aiding and abetting the persecutions, killings and forcible transfer of the Bosnian Muslim population of the Srebrenica enclave.
His prison sentence was accordingly cut to 15 years.
Blagojevic did not react to the new ruling until the judges walked out of the court, when he began shouting accusations about his court-appointed defence lawyer, Micheal Karnavas.
Blagojevic has refused to co-operate with Mr Karnavas.
"This is outrageous," he said.
"You are protecting the criminal behaviour of Karnavas in the court room."
The appeals panel also upheld the convictions of a second Bosnian Serb army officer who had been tried with Col Blagojevic in 2005.
Dragan Jokic was convicted of aiding and abetting murder and persecution at Srebrenica and given a nine-year prison sentence.
Jokic was the chief of engineers in the Zvornik brigade of the Bosnian Serb army in 1995. His troops dug the mass graves to bury the victims of the massacre.
At their original trial, Blagojevic and Jokic were acquitted of allegations of command responsibility for the atrocity. The tribunal ruled they had merely passed on orders.
The fugitive former Bosnian Serb leaders, Ratko Mladic and Radovan Karadzic, have been indicted for giving the orders.