Riots at two prisons in Ecuador on Wednesday left at least 18 dead and more than 50 injured, including police officers, authorities said, updating an earlier toll.

Elite police units have regained control of the two prisons, one in the southwest province of Guayas and the other in the central Andean province of Cotopaxi, the SNAI prisons management body said in a statement late Wednesday.

Ten inmates died and 35 others were injured, along with six police officers, in the violence at the Cotopaxi prison.

Eight inmates lost their lives and three police were injured at the Guayas facility.

The SNAI had earlier reported eight dead in Guayas and around 20 injured in Cotopaxi.

The two jails previously experienced violent riots in February, when clashes between rival gangs vying for control of the country's main prisons left 79 inmates dead in a single day.

In February's riots, inmates were left decapitated and burnt in violence that exposed the power of prison gangs and shocked the South American nation.

Ecuador's prison system has about 60 facilities with capacity for 29,000 inmates. But overcrowding is around 30 percent, with 38,000 detainees watched by 1,500 guards that experts say it would take 4,000 to effectively control.

According to the Ombudsman, there were 103 murders in Ecuador's prisons in 2020.

In an attempt to counter the violence, then-president Lenin Moreno had declared a state of emergency several times, including for three months last year.

Since the start of the pandemic, Ecuador has used alternative sentences for minor offenses to reduce the prison population and has managed to reduce overcrowding from 42 percent to about 30 percent.