Police in Brazil say 77 inmates are on the run after escaping amid a riot at a jail in the central state of Goias.
The authorities say nine prisoners were killed and 14 injured when a group of armed inmates invaded a wing controlled by a rival gang. One of the victims was decapitated.
Police say they have regained control of the jail and recaptured 29 of the 106 prisoners who escaped.
Riots are common in Brazilian prisons, which are notoriously overcrowded.
Brazil has one of the largest prison populations in the world. The country's jails are largely controlled by powerful criminal factions with access to drugs, mobile phones and weapons.
A report by judicial authorities in 2016 described security at the rural penitentiary on the outskirts of the state capital, Goiania, as "bad".
According to the report, the prison - part of a larger complex - was built to house 122 inmates, but at one point it held 423 inmates.
The riot began in the afternoon of New Year's Day when armed members of one criminal gang invaded a prison wing housing a rival gang, setting mattresses alight and firing weapons.
Riot police said they had quickly suppressed the riot, but not before 106 prisoners had escaped after breaking down part of the prison's perimeter wall.
'Five agents on duty'
"It was a clash between prisoners and it is all under control now," said Lieutenant-Colonel Hrillner Braga Ananias.
Worried relatives gathered outside the compound in Aparecida de Goiania.
"My brother is inside and I don't have any information about him," Luana Cristina told O Popular newspaper. "No-one tells us anything. No-one tells us who is dead, who is alive, who was shot," she added.
Jorimar Bastos, the head of Aspego, the state of Goias prison wardens' association, told Folha de Sao Paulo newspaper that only five prison officers were on duty on New Year's Day.
They were in charge of some 900 inmates across the whole complex, he said.