The Food and Drug Administration issued an unusual warning letter Thursday to a Canadian drug distributor, contending the company has sent “unapproved” and “misbranded” drugs to consumers in the United States, jeopardizing their safety.

The FDA urged U.S. consumers “not to use any medicines from CanaRx,” which supplies drugs to employees of about 500 cities and counties, and private-sector employers seeking discounts on drug prices. The FDA said the drugs include some subject to special rules and restrictions in the U.S. because they are potentially dangerous to users.

The FDA action comes amid a growing clamor over high drug prices in the U.S. that included a Senate hearing Tuesday at which top pharmaceutical executives were grilled about the costs.

FDA Commissioner Scott Gottlieb said in an interview that the move “isn’t timed with anything. This isn’t politically motivated. This is our bread and butter. This is public health protection 101.”

But Joseph Morris, a Chicago-based attorney for CanaRx, said he was baffled by the action and speculated the FDA may have made a mistake.

“We have not had any prior warnings, threats, complaints or communications with the FDA at all,” Morris said. “They seem to think we’re an Internet pharmacy contracting with plan sponsors to supply medications.”

Morris, however, said the company facilitates only the sale of medicine made by brand-name companies such as Pfizer and Merck licensed by the FDA — in the original packaging. He said individual consumers submit prescriptions from U.S. doctors. Those are rewritten by doctors in Canada, Britain and Australia and filled by bricks-and-mortar pharmacies in those countries, he said. The drugs are then mailed to consumers, who pay, on average, 30 percent of the price they pay here.

“American brand-name drugs only,” Morris said. “Our promise to our consumer is that we’re going to ship to her what her doctor ordered.”

Employers submit insurance claims and the company settles with the employer. The company does not supply opioids or products that do not travel well, such as insulin, Morris said.

The FDA said it has no reports of adverse reactions to drugs supplied by CanaRx. Rather, Gottlieb said in the interview, the FDA has tried to persuade CanaRx to reform practices that it contends allow counterfeit, adulterated, weak, super-potent and mislabeled drugs into the United States.

According to the warning letter, CanaRx offers drugs for cancer, HIV, hepatitis, epilepsy and other conditions.

“This is about safety,” Gottlieb said. “This is about creating very unsafe conditions for American consumers, and deceiving consumers.”

The FDA considers drug importation illegal, but in recent years, the number of U.S. cities, counties and school districts that help employees import drugs this way has grown. The FDA has not moved to crack down on them. Some states are looking at setting up similar systems, and Congress has repeatedly approved legislation allowing drug importation over the last 20 years that has never been implemented.

Millions of people also cross the border into Mexico or Canada to buy drugs at bricks-and-mortar pharmacies or purchase them via the Internet. The FDA does not prosecute them either.

In late 2017, however, the agency raided nine businesses in central Florida that helped customers, mainly older people, buy drugs from pharmacies in other countries, according to Kaiser Health News. Owners were warned they were operating illegally and could face fines or jail time.