BRASILIA (REUTERS) - A Brazilian court sentenced 23 police officers on Sunday to 156 years in jail each for killing 13 inmates in Brazil's bloodiest prison revolt in which 111 inmates died more than 20 years ago.

Military police stormed Sao Paulo's Carandiru prison in 1992 to quell a riot sparked by a fight between two rival gangs that started with a quarrel during a soccer game.

Prosecutors said police officers brutally repressed the uprising by shooting 102 prisoners, sometimes at point-blank range.

Another nine inmates are believed to have been killed with knives in the fight between prisoners.

The conviction of police officers is unusual in Brazil and the tough sentences handed down to those involved in the prison massacre was a new sign of the judiciary holding authorities accountable for breaking the law. Last year, in an unprecedented case, the Supreme Court convicted several top ruling party politicians of corruption.

The Carandiru massacre shocked Brazilians and exposed the awful conditions in Brazilian prisons. It became the subject of a hit 2003 film.

The prosecution's main witness was the former deputy director of the prison, Moacir dos Santos, who told the court that the military police "executed" the prisoners, many of them in their cells, even those who had surrendered and were naked.

"I saw a carpet of bodies," Santos said during the six-day trial. He said police went in machine-gunning inmates and officers outside cheered after the first wave of shootings.

Another witness, forensic expert Osvaldo Negrini Neto, said 90 percent of the shots were fired inside cells. No police officers died.

Defense lawyers argued that the police acted in self-defense when attacked by inmates trying to escape from the prison, Brazil's largest and most notorious penitentiary.

Three of the 26 indicted officers were acquitted. They were originally accused of the killing of 15 prisoners, but two of the deaths were found to have been caused by fellow inmates.

Another two trials of dozens more officers involved in the massacre are expected to follow. Most of the officers are retired now.

The officer who commanded the operation, Colonel Ubiratan Guimaraes, was sentenced to 632 years in jail for his role in the massacre, but the conviction was dropped when a mistrial was declared in 2006. Months later he was found dead in his apartment with a gunshot to the stomach.

The Carandiru prison was demolished in 2002.