QUITO/GUAYAQUIL, Ecuador (Reuters) -Ecuador is planning to pardon up to 2,000 inmates in order to relieve overcrowding at its detention centers after 118 inmates died and a further 79 were injured in the country's worst-ever prison riot earlier this week, an official said on Friday.

       Bolivar Garzon, the director of the South American country's SNAI prison authority, said the government aimed to prioritize the elderly, women, and prisoners with disabilities and terminal illnesses in the wake of the clashes on Tuesday at the Penitenciaria del Litoral in the southern city of Guayaquil.

       The country's prisons are currently home to some 39,000 inmates, Garzon added.

       Garzon said the riot, the latest in a wave of prison violence in the Andean country, was sparked by "a battle for control by organized crime groups." Riots left 79 dead in February and 22 in July of this year.

       Officials say gangs have alliances with transnational criminal groups and are battling over drug trafficking routes.

       Ecuador has sent 3,600 police and military reinforcements to prisons across the country to maintain order, Interior Minister Alexandra Vela told reporters on Friday. She added that forensic units had identified 41 of the victims, and had delivered the bodies of 21 of the victims to their families.

       Dozens of inmates' relatives have gathered outside a Guayaquil morgue seeking information about their loved ones. Authorities said at least six victims were decapitated.

       Eduardo Montes, 60, was awaiting news of his 25-year-old brother Vicente Montes, who is due to be released in one month.

       "They sent us a photo where you can see the head of one victim, and we believe it is my brother, but we do not know if he is really dead or if he is alive," Montes said. "I have hope that he is alive and that they release him."

       (Reporting by Alexandra Valencia in Quito and Yury Garcia in Guayaquil, Ecuador; Writing by Luc Cohen; Editing by Howard Goller and Aurora Ellis)