The massacre happened during the siege of Vukovar, Croatia
A Belgrade court has jailed 13 Serbs for up to 20 years for their part in a 1991 massacre of some 200 Croats.
Local commander Miroljub Vujovic and six others received 20-year sentences, while six more defendants received between five and 15 years.
But relatives of victims were angry that five defendants were acquitted.
The Croats were rounded up by Serbs during a siege of the town of Vukovar, taken to a pig farm, divided into small groups and machine-gunned down.
Those who were not killed outright were shot in the head with pistols.
This case had been seen as a test of the Serbian judiciary's readiness to punish Serbs guilty of atrocities.
The 13 were "guilty because they murdered, tortured and inhumanly treated prisoners of war" in the village of Ovcara near Vukovar, judge Vesko Krstajic told the court.
Lawyers for those jailed said an appeal would be lodged at the Supreme Court.
The initial trial of the suspects took place in 2005, but the verdicts were overturned in 2007 by the Supreme Court, citing procedural irregularities, and a retrial was ordered.
Prosecutors said they would appeal against the acquittals, but expressed satisfaction with the 13 convictions.
But relatives of the dead said they remained unhappy with the outcome.
"I am not happy with the decision of the Supreme Court personally as a mother because the verdict will not bring my son back," said Barica Spuric.
"I wish the world could see that crimes must be punished, so crimes like this will never happen again."
Another relative, Veronika Dusko, told Reuters news agency she was dismayed that the sentences "are so low. That's injustice, that's insane."
Among those acquitted was Milorad Pejic, a Serb who had relocated to the UK but was arrested when he flew to Belgrade to visit his mother last March.
Croatia's 1991 declaration of independence from the former Yugoslavia sparked a revolt by its ethnic Serbs, who were backed by the Serb-dominated federal military and Belgrade.
In November of that year, the army and Serb rebels captured Vukovar, razing the town and killing more than 1,000 civilians over a three-month period - including those at Ovcara.
The war ended in 1995, after Croatian forces re-took Serb-held territories.