WASHINGTON – Nearly 90 percent of the imported mail-order drugs stopped at the borders in a special crackdown by government agents were potentially dangerous, the Food and Drug Administration said Monday.

Of 1,153 imported drugs collected by FDA and Customs agents, 1,019 were found to be illegal. They included drugs that have been withdrawn from the U.S. market, animal drugs never approved for human use, counterfeit drugs, drugs with dangerous interactions, drugs with dangerous side effects and narcotics, officials said.

The drugs were collected at international mail arrival centers in New York, Miami, San Francisco and Carson, Calif.

Imported drugs have become a hot political issue in recent years with many Americans seeking lower-cost products from foreign sources.

Buying drugs from Canada is particularly popular because U.S.-produced drugs cost less there.