“At this moment, we have registered 18 prisoners injured, five police officers injured and five inmates killed,” the organization said on Twitter about the incident that took place on Wednesday.

The deaths came only days after clashes broke out Monday and Tuesday in another Ecuadorian prison in the city of Latacunga, leaving 16 prisoners dead and 43 injured.

The prison authority said the Guayaquil deaths were a result of “confrontations” between inmates at the Guayas 1 prison, which was the scene of four of the eight prison riots in Ecuador this year, which have seen nearly 400 people killed in total.

The organization did not specify whether the facility’s security forces had contained the violence.

Authorities Wednesday night had reported 11 injured, including five guards, who police said were attacked “with firearms while intervening to restore order.”

The prison authority said some of the inmates were injured by “explosives,” set off by the prisoners, which had also caused structural damage to the facility.

The clashes involved inmates from 12 sections of Guayas 1, which houses nearly 7,000 prisoners as part of a larger complex.