U.S. regulators warned 10 companies for violating a recently enacted ban on sales of flavored cigarettes, letters released on Friday showed.

The Food and Drug Administration told Clove Cigarettes Shop, Durango Smoke Shop Inc and the others to immediately stop marketing the products or to bring them into compliance with the law.

In September, the agency banned cigarettes with flavors such as grape and clove that can appeal to children. The move was required by a June law that gave the FDA sweeping powers over the tobacco industry. A major aim of the law is preventing youth from smoking and developing a lifetime habit.

Failure to comply with the ban could lead to product seizures or injunctions, the FDA said.

Menthol cigarettes are not subject to the ban.