The chaos in Culiacan, long a stronghold for the Guzmans' Sinaloa cartel, will increase pressure on President Andres Manuel Lopez Obrador, who took office in December promising to pacify a country weary after more than a decade of drug-war fighting. Murders this year are set to be at a record high.
Thursday's events follow the massacre of more than a dozen police in western Mexico earlier this week, and the killing of 14 suspected gangsters by the army a day later.
Falko Ernst, senior analyst for the International Crisis Group in Mexico, said the release of Ovidio Guzman set "a dangerous precedent" and sent a message that the state itself, including the army, could be blackmailed and was not in control.
Presumed cartel members apparently intercepted a radio frequency used by security forces, one video showed, warning of reprisals against soldiers if Guzman was not freed.
A state police spokesman confirmed to Reuters that several prisoners escaped from a prison during the chaos. Video footage showed a group of at least 20 prisoners running in the streets. It was not immediately clear how many had escaped.
"They are freeing them," a panicked woman said in the video apparently filmed from an tall building. "No we can't go outside!" she said as other voices debated making a dash for their car.
In another video, a man driving repeatedly shouted: "There is a big gunfight," before taking a sharp turn and leaving his car at a gas station to take cover. His voice then became inaudible because of the rattling roar of automatic gunfire.
'El Chapo' Guzman led the Sinaloa cartel for decades, escaping from prison twice before being arrested and extradited to the United States. He was found guilty in a U.S. court in February of smuggling tons of drugs and sentenced to life in prison.
He is believed to have about 12 children including Ovidio. The U.S. Department of Justice unveiled an indictment against Ovidio and another of the brothers in February, charging them with conspiracy to distribute cocaine, methamphetamine, and marijuana in the United States.
The indictment gave Ovidio's age as 28, and said he had been involved in trafficking conspiracies since he was a teenager.
Jose Luis Gonzalez Meza, a lawyer for the Guzmans, told news network Milenio that Ovidio had been in touch with the family and said he was free.
