Tanning beds and sun lamps in the US will carry new warnings that they should not be used by anyone under the age of 18.
The new warnings come as part of a government action aimed at reducing skin cancer linked to the radiation-emitting devices.
The Food and Drug Administration has regulated tanning machines for more than 30 years, but the agency is now requiring more prominent warnings about the cancer risks of indoor tanning.
Makers of sun lamps and related devices must include a bold label, known as a black box warning stating that they should not be used by people under age 18.
Additionally, manufacturers must provide more warnings about cancer risks in pamphlets, catalogues and websites that promote their products.
Those materials must warn that the devices shouldn't be used by people who have had skin cancer or have a family history of the disease.
For years, medical groups have urged the US government to take action on tanning beds because of rising rates of skin cancer among teenagers and 20-somethings, particularly women.
More than 76,000 new cases of melanoma, the deadliest form of skin cancer, are expected to be diagnosed this year, and the disease is expected to cause 9,710 deaths, according to the American Cancer Society.
While most cases are diagnosed in people in their 40s and 50s, the disease is linked to sun exposure at a young age.
But melanoma is also the second-most common form of cancer among young adults, according to the American Academy of Dermatology.An estimated 2.3 million US teenagers tan indoors each year.
A spokeswoman for the American Academy of Dermatology said she hoped the federal move would spur more states to take action. Twenty four states already have laws banning minors from using indoor tanning equipment.