Secretary of the Treasury Janet Yellen unveiled Wednesday sanctions against two companies and 15 people that the United States says have links to Mexican drug cartel.

“We cannot end the U.S. opioid crisis and achieve greater security without looking beyond our borders,” Yellen said in Mexico City, according to The Associated Press.

Yellen is in Mexico this week following a Treasury Department announcement of a strike force aimed at fighting illicit fentanyl trafficking.

The sanctions imposed on the 15 people and two companies were a result of their links, directly or indirectly, to the Beltran Leyva drug cartel, according to the Treasury Department, per the AP. Two people who the U.S. considers cartel leaders, musician Oscar Manuel Gastelum Iribe and Pedro Inzunza Noriega, were penalized alongside other group members, according to the Biden administration.

According to the Treasury, the cartel has been sending large amounts of drugs including cocaine and methamphetamine into the U.S. for decades and has a history of being “heavily involved in the transportation and distribution of deadly drugs, including fentanyl.”

“Drug trafficking organizations generate billions of dollars in illicit proceeds every year,” Yellen said, according to the AP. “They hold some in cash, some in investments, such as in real estate, and, increasingly, though still in small amounts, in digital assets. U.S. financial institutions are vulnerable, such as through exposure to drug trafficking organizations using shell companies.”

The new sanctions prevent the targeted people and companies conducting business with Americans, and block access to U.S. property and bank accounts.

The Associated Press contributed.