Federal health authorities on Monday blasted vaping company Juul for illegally pitching its electronic cigarettes as a safer alternative to smoking and ordered the company to stop making unproven claims for its products.

The Food and Drug Administration also upped its scrutiny of a number of key aspects of Juul’s business, telling the company to turn over documents about its marketing, educational programs and nicotine formula.

The FDA action increases the pressure on the nation’s best-selling vaping company, which has been besieged by scrutiny from state and federal officials since a recent surge in underage vaping. Federal law bans sales to those under 18. The FDA has been investigating Juul for months but had not previously taken action against the company.