MEXICO CITY (AP) -- The U.S. Treasury Department on Thursday sanctioned members of a Sinaloa cartel faction known as Los Mayos, one of the groups that has tormented Sinaloa's capital in an ongoing war for control.

The move came on the same day that U.S. Under Secretary of the Treasury for Terrorism and Financial Intelligence John K. Hurley is visiting Mexico, and after the Trump administration designated the Sinaloa cartel as a terrorist group earlier this year.

Hurley is meeting with Mexican authorities and business leaders to discuss strategies for combating drug trafficking, cartel operations and illicit financing. The U.S. Treasury Department said in a statement that the official's main message will be that the department "will not allow Mexico-based drug cartels to access the U.S. financial system."

It's part of an ongoing effort by the Trump administration to crack down on cartels. In addition to pressuring Mexico's government to more aggressively pursue the criminal groups, the administration has also doled out rounds of sanctions to cartel leaders, banks it alleged facilitated money transfers for cartels and a rapper accused of laundering money for the groups.

On Thursday, the U.S. Treasury sanctioned the entirety of Los Mayos, the leader of it's armed wing, Juan José Ponce Félix, as well as five people and 15 companies with alleged connections to the group along the U.S.-Mexico border. It froze all the assets of those listed in the sanctions, and blocked any transactions with them or any related entities or businesses. It also sanctioned another local gang affiliated with the cartel, known as Los Rugrats.

U.S. Treasury officials said that the faction was responsible for producing and trafficking fentanyl and other drugs to the United States and that it controlled a key artery along the border. They also alleged that the group was involved in kidnapping, money laundering and more near the U.S.-Mexico border.

The Los Mayos faction is responsible for producing and trafficking of fentanyl and other drugs from Mexico into the United States. In Baja California, Los Mayos is involved in kidnapping, extortion, money laundering, and local government corruption, and uses border areas in the state as key arteries for drug trafficking.

Los Mayos are a faction of the Sinaloa cartel loyal to former cartel leader Ismael "El Mayo" Zambada who pleaded guilty to drug trafficking charges in U.S. federal court last month. For more than a year, the faction has been locked into open warfare in the city of Culiacan with Los Chapitos, another faction of the cartel led by sons of former Sinaloa cartel kingpin Joaquín "El Chapo" Guzmán.