The emergency declaration seemed to set off violence in the city of Esmeraldas, where 15 prison guards and two other staffers were being held hostage at a local jail, the government said in a statement.

In Esmeraldas itself, a police unit was attacked, explosives were placed at gas stations and several cars were burned. The attorney general's office said on social media that one civilian was hurt in a Molotov cocktail attack on its office there.

In Guayaquil, at least 2,700 heavily equipped soldiers and police officers entered the Penitenciaria del Litoral prison after enactment of the 60-day measure, regaining control of three cellblocks with controlled detonations.

Clashes between gangs began on Saturday at the prison, one of the most dangerous in Ecuador.

The prosecutor's office raised the death toll to 31 from 18 in a post on social media platform X, formerly known as Twitter. It also raised the number of injured to 14.

Some 120 prison officers had been freed after being held hostage in six jails around the country, the government said. There was no official information about hunger strikes allegedly taking place at some prisons.

This latest surge of prison violence comes during campaigning for Aug. 20 elections, with some presidential candidates pledging prison reforms.

According to the decree signed by President Guillermo Lasso, inmates in Guayaquil used firearms during the unrest and set fire to facilities using gas tanks.

Lasso on Monday declared a state of emergency in the provinces of Manabi and Los Rios and in the city of Duran, after the mayor of the city of Manta, Agustin Intriago, was shot dead on Sunday.

Military intervention in Ecuador's prisons will continue until control has been retaken and there is no threat to prisoners or officials, the government said.

Lasso has regularly declared states of emergency in the country's prisons as he tries to tackle violence that has surged since 2021, claiming the lives of hundreds of prisoners.