Three prisoners were decapitated and seven others were killed at a prison in the northeastern Brazilian city of Natal, police said Sunday. The deaths were the result of a riot that broke out at the Alcacuz Penitentiary — the largest jail in Rio Grande do Norte state.

Police managed to regain control of the prison 14 hours after the riots started on Saturday afternoon. Security forces managed to enter the outer area of the prison but decided to wait for daylight hours before going in on Sunday morning. No prisoners were reported to have escaped. 

“We could see the heads ripped off” of three inmates, Zemilton Silva, coordinator of the prison system, reportedly said.

The prison, which currently holds some 1,150 prisoners, houses about twice as many inmates as it was initially supposed to hold.

This is the fourth such riot in Brazilian jails since the start of this year. According to media reports, about 100 people have died in the states of Amazonas and Roraima over the past two weeks. Riots are a common scene in Brazil’s prisons, which are often overcrowded and largely controlled by powerful criminal gangs. However, the scale of the riots this year has put pressure on President Michel Temer to address the issue.