A clash between prisoners in one of Ecuador's largest jails - in Latacunga - has left at least 15 inmates dead, the authorities report.
The national prisons agency Snai said prisoners had fought with guns and knives, before guards managed to regain control. It is 80km (50 miles) south of the capital Quito.
Ecuador has had a spate of deadly clashes between drugs gangs in prisons.
Efe news agency says more than 400 have died in those clashes since 2020.
Ecuadorean media report that those killed in the clash at Latacunga's Cotopaxi jail included an alleged drug gang boss, Leandro Norero. He was arrested in May on money-laundering charges.
The violence erupted after a census of prisoners. It came shortly after UN torture prevention experts visited Ecuador to assess its efforts to curb prison violence.
In April Ecuador's President Guillermo Lasso declared a state of emergency in three provinces to curb gang-related violence linked to drug-trafficking. A similar emergency was declared last year.
The turf wars between Ecuadorean gangs fighting for control of lucrative cocaine networks have put huge strain on the under-resourced and overcrowded prison system.
The worst prison clash was in the port city of Guayaquil in September last year, when more than 120 inmates died.
Last year Ecuador's police seized a record 190 tonnes of drugs, mostly cocaine.
