At least 58 inmates have died following a gun battle between rival gangs inside Ecuador's largest prison.
It is the latest violence to hit the Litoral Penitentiary, which only a few weeks ago was the scene of the country's worst prison massacre.
The fighting lasted for almost eight hours in the jail in the coastal city of Guayaquil.
Authorities have blamed prison gangs linked to international drug cartels for the violence.
Governor Pablo Arosemena of Guayas province, where Guayaquil is located, said inmates "tried to dynamite a wall to get into pavilion two to carry out a massacre. They also burned mattresses to try to drown (their rivals) in smoke.
"We are fighting against drug trafficking. It is very hard."
Police commander Tanya Varela said authorities using drones saw that inmates were armed with guns and explosives.
Authorities said that besides the 58 dead, 12 inmates were injured and officials seized bombs and guns.
The prison violence comes amid a national state of emergency ordered by Ecuador's president Guillermo Lasso in October that allows security forces to fight drug trafficking and other crimes.
Ecuador's jails are seeing a wave of brutal violence.
In late September, another battle among gang members in Litoral prison killed at least 118 people in what authorities described as the South American country's worst ever prison massacre.
Officials said at least five of the dead were beheaded.
In February, 79 inmates were killed in simultaneous riots in various prisons. So far this year, more than 300 prisoners have died in clashes in jails across the country.