At least 40 inmates have been found dead at separate prisons in northern Brazil a day after 15 prisoners were killed in gang clashes, officials say.
The latest deaths, which were reported in Manaus, the capital of Amazonas state, all appeared to be the result of asphyxiation, authorities said.
They added that staff had discovered the victims during routine inspections at four different prison facilities.
A task force has been sent to “control the disturbances,” officials said, according to a BBC News report on Tuesday.
Several other inmates were injured in Monday’s incidents, according to Brazil’s Globo news website in Portuguese.
The majority of the victims were discovered at the Antônio Trindade institute near Manaus, while deaths were also reported at the Puraquequara and Provisional Detention Centre facilities in Amazonas state.
The local governor, Wilson Lima, described the situation on Monday as a “crisis”.
He added that an investigation launched on Sunday would be extended to include the latest deaths.
On Sunday, clashes reportedly broke out during visiting hours at Anísio Jobim Penitentiary Complex in the region.
Officials said the prisoners had been stabbed with sharpened toothbrushes and strangled to death.
The violence over the weekend was witnessed by visitors.
“It was total chaos,” the mother of an inmate – who did not wish to be named – told the Rio Times.
“Everyone started to run, and everyone was pounding on the cell gates, at the doors, and running down the corridors.”
It comes two years after infighting killed 56 at the same jail, one of the deadliest riots ever in a Brazilian prison.
Brazil has the world’s third-largest prison population – 712,305 inmates in April this year, according to official figures.
The population is nearly double the capacity of Brazil’s prisons. The overcrowding has led to gang violence, riots and sometimes breakout attempts.
In early 2017, several violent rebellions left 119 people dead in jails in northern Brazil.
About 92 inmates also escaped last September after heavily armed men set off explosives outside a prison and shot their way inside, killing a policeman.
Attempts to reform the prison system and to introduce tighter controls have met with resistance from powerful criminal gangs which operate both inside and outside of jails.
Earlier this year, gangs launched around 80 attacks on public buildings, banks, buses and petrol stations – many of them believed to have been carried out in retaliation for the proposed reforms.