The Food and Drug Administration and international law enforcement announced Tuesday that they are targeting 465 websites that illegally sell opioids and potentially dangerous drugs marketed as cures for cancer.

The effort is part of an annual global campaign coordinated by the international law enforcement agency Interpol to crack down on the distribution of illegal and counterfeit drugs.

“The illegal online pharmacies that we’re taking action against are often run by sophisticated criminal networks that knowingly and unlawfully distribute illicit drugs, including potentially counterfeit medicines and controlled substances both on the surface and dark web,” said FDA Commissioner Scott Gottlieb in an announcement of the crackdown.

[Also read: FDA considers requiring co-prescribing overdose antidote to go along with opioids]

As part of the crackdown, called Operation Pangea XI, the FDA sent warnings to seven different networks operating 465 websites that were offering up misbranded or unapproved drugs. This is the 11th annual operation.

Some of the domains include seemingly innocuous names like or

The agency and Interpol also targeted the infrastructure that supports illegal online sales of drugs.

Cybercrime investigators focused on credit card processors involved in an arrangement called “transaction laundering,” through which businesses use shell companies like a florist or clothing store to process online payments for illegal online drug sales.

“The FDA’s investigation of these payment schemes led to a federal indictment charging a complex conspiracy related to transaction laundering for online pharmacies,” the agency said.

Illicitly created fentanyl has become a major contributor to the opioid crisis over the last few years. Of the more than 42,000 opioid overdose deaths in 2016, more than half were attributed to fentanyl.

Fentanyl is often shipped from overseas to the U.S. and payment is made via an online pharmacy.

A major legislative package expected to be signed by President Trump Wednesday aimed at combating the opioid crisis included a bill to give the U.S. Postal Service more tools to identify suspicious shipments of fentanyl.