WASHINGTON (AP) — The Biden administration on Tuesday imposed sanctions on 13 members of Mexico’s powerful Sinaloa cartel and four Sonora, Mexico-based firms accused of trafficking fentanyl and other drugs into the United States.

The latest action follows a series of measures taken this year against members of the Sinaloa cartel, cash couriers and cartel fraud schemes.

Included in the sanctions are a manager of cartel operations in Nogales who oversaw the trafficking of multi-ton quantities of drugs, authorities said, as well as members of his family and his associates. Also sanctioned are a restaurant, stone and mining companies and an import-export firm.

The sanctions cut them off from the U.S. banking system, cut off their ability to work with Americans and block their U.S. assets.

The Treasury Department’s undersecretary for terrorism and financial intelligence, Brian Nelson, said that the U.S. “will aggressively pursue all who are complicit operators and facilitators of these illicit fentanyl networks.”

The Treasury “will continue to use its authorities to expose and isolate those who profit from deadly fentanyl sales in the United States,” Nelson said.

Fentanyl, a powerful opioid, is the deadliest drug in the U.S. today.

The Centers for Disease Control and Prevention says that drug overdose deaths increased more than sevenfold from 2015 to 2021. More than 100,000 deaths a year have been linked to drug overdoses since 2020, and about two-thirds of those are related to fentanyl.

Mexico and China are the primary sources for fentanyl and fentanyl-related substances trafficked directly into the U.S., according to the Drug Enforcement Administration, which is tasked with combating illicit drug trafficking. Nearly all the precursor chemicals that are needed to make fentanyl come from China. And the companies that make the precursors routinely use fake return addresses and mislabel the products to avoid being caught by law enforcement.

In October, President Joe Biden’s administration announced a sweeping series of indictments and sanctions against Chinese companies and executives blamed for importing the chemicals used to make the deadly drug.

Republicans have complained, however, that the Democratic administration isn’t doing enough to stop fentanyl and the issue is likely to figure prominently in next year’s presidential campaign.