"We have to find out the extent of the problems."

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A federally-funded study last year found that one in five senior US high school students reported vaping nicotine in the previous month, twice as many as the previous year.

US health authorities last week urged Americans to stop using e-cigarettes while they investigate a sudden outbreak of lung disease linked to vaping.

Many of the cases under investigation involved smoking products containing THC, the active ingredient in marijuana.

Health and Human Services Secretary Alex Azar said: "The Trump administration is making it clear that we intend to clear the market of flavoured e-cigarettes to reverse the deeply concerning epidemic of youth e-cigarette use that is impacting children, families, schools and communities.

"We will not stand idly by as these products become an on-ramp to combustible cigarettes or nicotine addiction for a generation of youth."

Earlier this week the Food and Drug Administration (FDA) said that Juul, which controls more than 70 per cent of the US market, had illegally marketed its vaping products as a less harmful alternative to traditional cigarettes.

The FDA has described youth vaping in the US as an "epidemic".

Flavoured e-cigarettes are seen as particularly alluring to young people who have never smoked cigarettes before.

Juul e-cigarettes, which resemble a flash drive, are so discreet that students have been able to smoke them in class without teachers noticing.

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Administration officials said it would take several weeks to develop the proposed flavour restrictions, and they will be subject to public input before taking effect.

Retailers will still be able to sell tobacco-flavoured e-cigarettes to adults.

Michigan this month became the first US state to ban flavoured e-cigarettes and states such as New York are preparing to follow.

The American Vaping Association said it was disappointed that Trump was bowing to pressure from "anti-vaping activists" such as former New York mayor Michael Bloomberg.

"A ban will remove life-changing options from the market that have been used by several million American adults to quit smoking," the association said.