Federal officials have warned promoters of more than 140 products sold over the Internet about fraudulent claims that they can prevent, treat or diagnose swine flu.

Bogus products include devices and sprays that claim to sterilize the air or surfaces, and dietary supplements claiming to boost the immune system. The U.S. Food and Drug Administration says it even has found fake Tamiflu being sold online without a prescription.

Officials say the problem has grown in recent weeks as vaccine is delayed and real Tamiflu continues to be reserved for only the sickest flu patients.