WASHINGTON — Federal health authorities say vaping giant Juul Labs illegally pitched its electronic cigarettes as a safer alternative to smoking, including in a presentation at schools.

The Food and Drug Administration issued a stern warning letter to the company Monday, flagging various claims by Juul, including that its products are "much safer than cigarettes." The FDA has been investigating Juul for months but had not previously warned the company.

The FDA letter highlights an incident recounted by two New York high school students during a congressional hearing last month. The students said a representative of Juul was invited to address the school on addiction issues. During the presentation, the representative told students the company's product was "totally safe."

Juul says it discontinued its school programs last September.