In an escalation of violence in northern Sinaloa, home to one of Mexico’s most powerful drug cartels, Mexican military forces have come under attack, and roadblocks have been established. The Sinaloa state security ministry confirmed these attacks occurred around the state capital, Culiacán, known as the stronghold of the imprisoned drug lord Joaquín “El Chapo” Guzmán and his sons, on Thursday.

Armed men attacked a military patrol in the Peñasco area on the outskirts of Culiacán while roadblocks were set up in the nearby town of Limón de Los Ramos, according to the security ministry on social media platform X. Governor Rubén Rocha stated that the assailants set two vehicles on fire “to obstruct the authorities.” He did not specify a motive for these attacks.

Local media have published video and images of the burning vehicles, a common tactic used to prevent police or military units from reaching a specific area. There are fears that the violence could further spread in Sinaloa, especially following recent arrests of top drug lords from the Sinaloa cartel.

In July, Joaquín Guzmán López, one of El Chapo’s sons, was allegedly involved in the kidnapping of Ismael “El Mayo” Zambada, an elder leader from a rival faction of the cartel. The kidnapping reportedly involved Zambada being forcibly put on a plane heading north, leading to much speculation. Guzmán López claimed they were going to “look at property,” but Zambada was instead flown to the United States.

Mexican authorities believe the kidnapping may be connected to the arrest of Ovidio Guzmán, another of El Chapo’s sons, who was arrested in January 2023 and later extradited to the U.S. On Thursday, the Mexican state prosecutorial authority urged U.S. authorities to “quickly” clarify Ovidio Guzmán’s legal status and whereabouts.

In a statement, the agency noted that Ovidio Guzmán was taken out of U.S. prison on July 23, just two days before the arrest of his brother and Zambada. U.S. Ambassador to Mexico, Ken Salazar, confirmed on July 26 that Ovidio Guzmán remains in U.S. custody without further information regarding his location.

Experts, including former Drug Enforcement Administration (DEA) agent Mike Vigil, suspect that Guzmán López may have betrayed Zambada to gain advantages for himself and his brother Ovidio. Zambada appeared in a Texas court this month in a wheelchair and pleaded not guilty to charges of drug trafficking, money laundering, and conspiracy to commit murder.

Guzmán López was transferred to Chicago, where he denied charges of drug trafficking, and he is currently serving a life sentence. Only one of El Chapo’s sons, Iván Archivaldo, accused of connections to the cartel, remains at large. The U.S. has offered a reward of $10 million for information leading to his capture.