The U.S. Food and Drug Administration unveiled a series of graphic images Tuesday that will appear on cigarette packages meant to warn of the dangers of smoking tobacco.

The warnings feature pictures of rotting teeth, diseased lungs and dying cancer patients. The images must appear on the top half of the front and back labels of all cigarette packages by October of next year. Warnings must also make up one-fifth of all tobacco advertisements.

The announcement is part of the 2009 Family Smoking Prevention and Tobacco Control Act, which gives the federal government authority to regulate tobacco products.

Although smoking rates have steadily declined for decades, studies show that about 20 percent of Americans still smoke tobacco.

American cigarette packages have featured small warnings on the side of packages for over 25 years, but many say the current messages are not effective enough.

Tobacco maker RJ Reynolds has challenged the legality of the new warnings in a federal lawsuit, saying the images make it difficult or impossible to successfully advertise the product.