Thirteen inmates died at the weekend in a prison in Ecuador that has seen 44 killed in violence in the past month, authorities said Monday. The deaths occurred Sunday at a prison in the coastal city of Machala in the southwest of the country and are now under investigation.

The state prison authority SNAI said in a statement that the bodies were found by police after "the detonation of an explosive device" outside the prison.

According to local media reports, the deaths were the result of asphyxiation.

The explosion, about 325 feet from the prison, was caused by a drone used to distract prison guards, the reports said.

SNAI said autopsies and "routine procedures" were being carried out to determine the causes of death.

Thirty-one inmates died in the same prison last month, many by asphyxiation, after a deadly armed riot. At the end of September, 14 others, including one prison guard, died in another armed confrontation there.

According to the Inter-American Commission on Human Rights, at least 663 prisoners have died in violence inside Ecuadorian prisons since 2020. Periodically, images of mutilated or burned bodies in its prisons go viral on social media.

President Daniel Noboa advocates a hardline policy against organized crime, similar to that of his Salvadoran counterpart, Nayib Bukele, and in 2024 he declared the country to be in a state of internal armed conflict to confront the cartels.

Another clash between drug gangs in September claimed at least 17 lives at a prison located in the coastal city of Esmeraldas, near the Colombian border.

Last year, a series of coordinated riots across multiple prisons led to the hostage-taking of 150 prison guards.

Ecuador's prisons have become among the deadliest in Latin America as overcrowding, corruption and weak state control have allowed gangs connected to drug traffickers in Colombia and Mexico to proliferate.

Last month, one of Ecuador's most wanted drug traffickers was captured, years after he faked his death and moved to Spain.  Wilmer Chavarria, also known as "Pipo," is believed to be the leader of Los Lobos, a drug trafficking group that was recently designated a terrorist organization by the United States.

Earlier this year, another leader of Los Lobos, Carlos D, was arrested at his home in the coastal city of Portoviejo. 

The U.S. last year declared Los Lobos to be the largest drug trafficking organization in Ecuador.

Criminal gang violence continues unabated in Ecuador following the recapture in June of the country's biggest drug lord, Adolfo Macías, who leads the Los Choneros gang, after his escape from a maximum-security prison in 2024. In July, the Ecuadoran government extradited Macias to the United States, where he faces multiple drug trafficking and firearms charges.