Con artists posing as U.S. Food and Drug Administration agents are trying to extort money from people who buy medications online and over the telephone, the agency warned on Tuesday.

The FDA, which is charged with protecting consumers, says these fake government officials gather people's personal information from online transactions, questionnaires and consumer lists and then call them demanding fines.

The scammers tell victims that buying drugs over the Internet or telephone is illegal and threaten them with prosecution unless a fine or fee ranging from $100 to $250,000 is paid, the agency said in a statement.

"If you refuse to pay up, the caller threatens to search your properties, arrest or deport you, put you in jail, and even physically harm you," the FDA said.

The problem is being investigated by FDA agents with help from other federal agencies, including the Drug Enforcement Administration, Immigration and Customs Enforcement and the Department of Homeland Security.

Authorities acknowledge that scams of this kind are hard to trace. The crooks can sound convincing if they're armed with your address, phone number, Social Security number, date of birth, purchase history and credit card account number.

"The best thing they can do is ignore the caller and hang up," said Philip Walsky, special agent in charge at FDA's Office of Criminal Investigations. He stressed that true FDA agents do not call up consumers to demand payment.

The good news for frightened consumers is that no one is known to have been approached in person, so there is little danger of a physical threat. In fact, most of the fraudulent callers are overseas.

Nor is buying drugs online illegal, though the FDA has warned consumers that some websites peddle unsafe medicines and offered advice on how to identify trustworthy Internet pharmacies. 

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