WASHINGTON — The federal government will act to ban thousands of flavors used in e-cigarettes, President Donald Trump said Wednesday, responding to a recent surge in underage vaping that has alarmed parents, politicians and health authorities nationwide.

The surprise White House announcement could remake the multibillion-dollar vaping industry, which has been driven by sales of flavored nicotine formulas such as “grape slushie” and “strawberry cotton candy.”

The Food and Drug Administration will develop guidelines to remove from the market all e-cigarette flavors except tobacco, Health and Human Services Secretary Alex Azar told reporters during an Oval Office appearance with the president, first lady Melania Trump and the acting FDA commissioner, Ned Sharpless.

Trump, whose son Barron is 13 years old, said vaping has become such a problem that he wants parents to be aware of what’s happening. “We can’t allow people to get sick and we can’t have our youth be so affected,” he said.

Melania Trump recently tweeted her concerns over the combination of children and vaping.

Trump’s first public comments on vaping come as health authorities investigate hundreds of breathing illnesses reported in people who have used e-cigarettes and other vaping devices.

No single device, ingredient or additive has been identified, though many cases involve marijuana vaping devices.

The restrictions announced by Trump officials would only apply to nicotine vaping products, which are regulated by the FDA.

The FDA has had the authority to ban vaping flavors since 2016, but has previously resisted calls to take that step. Agency officials instead said they were studying if flavors could help smokers quit traditional cigarettes.

But parents, teachers and health advocates have increasingly called for a crackdown on flavors, arguing that they are overwhelmingly to blame for a recent surge in underage vaping by U.S. teens, particularly with small, discrete devices such as Juuls.

Anti-tobacco groups praised the announcement but said action must be “immediate.”

“It has taken far too long to stop Juul and other e-cigarette companies from targeting our nation’s kids with sweet-flavored, nicotine-loaded products,” said Matthew Myers, of the Campaign for Tobacco-Free Kids, in a statement.

A ban on flavors would be a huge blow to companies like San Francisco-based Juul, which sells mint, fruit and dessert flavored-nicotine pods.

Juul and other manufacturers argue that their products are intended to help adult smokers wean themselves off traditional paper-and-tobacco cigarettes. But there is little evidence that e-cigarettes are effective for helping smokers quit.

The Vapor Technology Association said in a statement the flavor ban would force smokers “to choose between smoking again ... or finding what they want and need on the black market.” The group represents vaping manufacturers, retailers and distributors.

Federal law prohibits e-cigarette and all other tobacco sales to those under 18. But last year, 1 in 5 high school students reported vaping in the past month, according to government survey figures.