Eleven inmates and a police officer were killed in a stand-off between inmates and security forces at a jail in Paraguay on Monday.
Prisoners opened fire on police as they entered the jail in the capital Asunción to transfer a notorious drug lord, Armando Javier Rotela.
Police said Rotela controlled a part of the jail dubbed The Jungle, where he ran a small supermarket.
Officers also seized three pit bulls and several fighting cockerels.
Police commissioner Nimio Cardozo said Rotela, who leads the criminal clan of the same name, lived in comfort in The Jungle along with his pregnant wife, his dogs and his cockerels.
Mr Cardozo told journalists that it had taken 2,500 soldiers and police officers to regain control of the Tacumbú penitentiary.
He said that one policeman had died from a bullet wound to the head and another was seriously injured. Dozens more inmates and security personnel were also wounded in the gunfight.
Mr Cardozo said about 700 inmates, including Rotela himself, had been relocated to other prisons.
The authorities have been trying to break up the Rotela Clan and weaken the grip it had on Tacumbú prison for months.
Officials have not yet said where the clan’s leader has been moved to.
Over the past 20 years, the 41-year-old Rotela has become one of the most powerful criminals in Paraguay.
First detained for cattle raiding in 2000, he has also been convicted of robbery before becoming known as Paraguay’s “crack czar” for his control of the illegal drugs market.
He is infamous for recruiting women and children to deliver drugs to buyers, as they attract less police attention.
When he was arrested in 2011, police found large quantities of cash submerged in plastic bags in a pond on his property.
He managed to escape from prison the following year and was on the run until 2016, when he was re-arrested.
Analysts say he has continued to expand his drug trafficking business from behind bars.
Paraguay is not the only country in the region to struggle to regain control of jails which for years have been run by inmates.
In Venezuela, the leader of a gang-run “luxury” jail, complete with a mini-zoo and baseball pitch, escaped in September and is still on the run.