Mexico's defence minister confirmed on Friday that authorities released a son of drug kingpin Joaquin "El Chapo" Guzman after his arrest triggered an all-out gun battle on the streets of Culiacan, capital of their cartel's bastion, Sinaloa.Luis Sandoval said soldiers arrested Ovidio Guzman - one of several sons who have taken control of the Sinaloa cartel since their father was extradited to the United States - but released him after being overpowered by cartel gunmen Thursday, in what he admitted was a "badly planned" operation."It was a badly planned strategy," Sandoval told a news conference in Culiacan, where he and other members of President Andres Manuel Lopez Obrador's security cabinet held an emergency meeting."The task force acted too hastily. (The operation) wasn't improvised, there was planning, but... it takes time to obtain an arrest warrant. When the operation was already under way, they decided to improvise and attempt to" get a warrant and arrest Guzman, he said.He added that Guzman was never "formally detained".Heavily armed cartel gunmen surrounded the house where Guzman was being held on Thursday afternoon and launched a massive assault on various parts of the western city of 750 000 people, sending terrified residents fleeing for safety.Lopez Obrador, who faced a firestorm of criticism over the episode, defended the decision to free Guzman."I support the decisions that were made. The situation turned very difficult and many citizens' lives were at risk, many human beings," he told a separate news conference."Catching a criminal can't be worth more than people's lives," added the leftist leader."This decision was made to protect the people. You can't fight fire with fire."