The United States has said it was imposing visa restrictions on 13 people linked to Indian online pharmacy KS International Traders for selling counterfeit prescription pills laced with fentanyl.

The 13 people are close associates of KS International Traders, which operates out of India, and its owner, the US State Department said on Tuesday.

The Mumbai-based company’s web site, as listed in US government records, could not be accessed. No names or contacts of its senior executives were available.

India’s foreign and health ministries did not immediately respond to requests for comment.

KS International Traders generated revenue through trafficking in fentanyl, which President Donald Trump has designated as a “weapon of mass destruction”, the State Department said.

Fentanyl is a powerful synthetic opioid used for pain relief, but it is tightly restricted in the United States because of its high potency and its role in a surge in overdose deaths linked to illicit use.

“Illicit fentanyl is killing too many Americans. Those complicit in poisoning Americans will be denied entry to the United States,” State Department spokesperson Thomas Pigott said in a statement.

This is not the first time that the US government has pulled up KS International Traders.

The online pharmacy, along with two Indian nationals, was sanctioned last year for supplying counterfeit fentanyl-laced pills.

The company sold hundreds of thousands of counterfeit prescription pills containing illicit fentanyl to people in the US, harming families and communities nationwide, the State Department said on Tuesday.

The US last year announced a new visa restriction policy aimed at stopping the flow of fentanyl and other illicit drugs into the country.