U.S. Treasury sanctions Sinaloa cartel faction Los Mayos in Mexico

The U.S. Treasury Department on Thursday sanctioned members of the Sinaloa cartel faction known as Los Mayos, a group that has fueled violence tied to the cartel’s long-running power struggle in Sinaloa state. The Treasury named the faction’s leadership and extended measures to five individuals and 15 companies with alleged ties to Los Mayos along the U.S.-Mexico border. It froze the assets of those listed and blocked any transactions with them or related entities. The department also sanctioned Los Rugrats, a local gang affiliated with the cartel. The Treasury said the designated individuals and entities are connected to the production and trafficking of fentanyl and other drugs moving into the United States, and that the faction maintains control over a key border artery used to move contraband.

The sanctions come as U.S. Under Secretary of the Treasury for Terrorism and Financial Intelligence John K. Hurley arrives in Mexico for meetings with government and business leaders. Hurley’s agenda includes discussions on strategies to disrupt drug trafficking networks, cartel operations and illicit financing, with the message that the United States will not allow Mexico-based drug cartels to access the U.S. financial system. Officials described Hurley’s visit as part of an ongoing effort to increase pressure on criminal networks that span both countries.

The action is part of a broader U.S. push to crack down on cartels operating across the border. Since earlier this year, the Trump administration has designated the Sinaloa cartel as a terrorist organization, a move aimed at expanding financing and asset-control tools against the group. In addition to sanctions targeting cartel leaders, the United States has also sanctioned banks alleged to facilitate money transfers for cartels and individuals accused of laundering cartel proceeds.

According to the Treasury, Los Mayos is responsible for producing and trafficking fentanyl and other drugs from Mexico into the United States. The faction is said to exercise influence in Baja California, where it is involved in kidnapping, extortion, money laundering and local government corruption, and where border-area routes are used as key arteries for trafficking. The department emphasized that Los Mayos operates as a loyalist faction within the broader Sinaloa cartel, aligned with Ismael “El Mayo” Zambada, the cartel’s longtime leader who pleaded guilty to drug trafficking charges in U.S. federal court last month.

For more than a year, Los Mayos and Los Chapitos — the latter a faction led by the sons of former Sinaloa cartel kingpin Joaquín “El Chapo” Guzmán — have been locked in open warfare in the city of Culiacán. The fighting has underscored the persistent instability in the region and the ongoing challenge for authorities seeking to restore control and reduce the violence that spills across the border into California, Arizona and Texas.

The Treasury’s designation underscores a broader strategy to choke off the material support networks that sustain cartel activity, including the illicit finance that underpins fentanyl production and cross-border shipments. Officials said the sanctions are designed to disrupt the financial flows that enable the illicit operations, from money transfers to the purchase of weapons and the maintenance of criminal infrastructure. By targeting a network that spans individuals, companies and border-area businesses, the United States aims to complicate the cartel’s ability to move money and goods across the border.

U.S. authorities have stressed the need for continued cooperation with Mexican authorities to dismantle transnational criminal networks. Hurley’s visit is expected to include discussions with Mexican officials about reinforcing law-enforcement collaboration, enhancing financial-tracking capabilities, and addressing illicit finance channels used by cartels. The Mexican government has long sought to balance enforcement with social and economic initiatives in the northern border region, where cartels operate in a competitive and highly violent environment.

Analysts note that the Los Mayos designation reflects a broader pattern of U.S. actions that tie criminal activity to the financial system. By freezing assets and prohibiting transactions, the Treasury Department aims to elevate the consequences for those involved in trafficking and related criminal enterprises, while signaling to other actors that the United States will pursue financial penalties as a core tool of national security policy.

While sanctions can constrain the operations of individual operators and companies, observers caution that cartel networks are resilient and adapt to enforcement. The ongoing violence in Culiacán and the persistent trafficking routes along the Baja California corridor illustrate the dual challenge of pressuring criminal organizations while addressing the social conditions that fuel their reach. The latest move, however, is likely to disrupt at least part of Los Mayos’ financial ecosystem and his ability to fund expansion or violence, at a time when Washington is pressing for more aggressive action against fentanyl-smuggling networks.

As the U.S. and Mexican authorities pursue a coordinated approach to dismantle the cartel’s financing channels, the Los Mayos designation adds to a set of measures designed to degrade the operational capacity of one of the most entrenched criminal groups in the region. The scope of the sanctions highlights the complexity of cross-border criminal networks and the ongoing need for information-sharing, law enforcement coordination and sustained political will to address the roots of violence and illicit trade that span the Americas.