Attorneys general from 29 US states urged the FDA on Friday to strengthen its proposed regulation on electronic cigarettes to better protect young people from nicotine addiction.

In a letter, attorneys general from states including New York, Illinois, Indiana and Massachusetts asked the FDA to prohibit flavors other than tobacco and menthol, and to restrict advertising and marketing for e-cigarettes as strictly as it does for cigarettes, according to a press release from New York Attorney General Eric Schneiderman.

“While we applaud the FDA’s proposal to start regulating these tobacco products, it falls far short of what is needed to protect our youth,” Schneiderman said.

The push by the attorneys general comes as the e-cigarette industry, backed by tobacco companies, expands its marketing across the country. More than 14 million US adults and almost 2 million teenagers and children aged 10-12, dubbed “tweenagers,” have used e-cigarettes.