The US surgeon general says that the increased use of e-cigarettes among young people represents a “major public health concern,” The Washington Post reports, and is calling on lawmakers to implement regulations that would curb their use among American youth. In a report to be released on Thursday, Surgeon General Vivek Murthy says that although there is a need for further research on the long-term effects of e-cigarettes, exposure to nicotine through vaping poses serious health risks to young people.

“We know enough right now to say that youth and young adults should not be using e-cigarettes or any other tobacco product, for that matter,” Murthy said in an interview with the Post. “The key bottom line here is that the science tells us the use of nicotine-containing products by youth, including e-cigarettes, is unsafe.”

“Young adults should not be using e-cigarettes or any other tobacco product.”

The report, which focuses on vaping among young people, acknowledges that e-cigarettes are less harmful than traditional cigarettes, as previous research has shown. But the surgeon general says there is not strong evidence that the devices are effective at helping people to quit smoking cigarettes, and concludes that vaping is “strongly associated” to the use of other tobacco products. A report from the Centers for Disease Control and Prevention (CDC) found that 3 million American teenagers used e-cigarettes in 2015, marking a ten-fold increase over four years.

The surgeon general’s warnings contrast with a report published earlier this year by the Royal College of Physicians in the UK, which said that e-cigarette use should be encouraged as a healthier substitute for tobacco cigarettes. That report, released in April, concluded that e-cigarette use in the UK is “limited almost entirely to those who are already using, or have used, tobacco,” and said that the products can be seen “as a gateway from smoking.” The long-term effects of e-cigarette use remain unclear, though a study released in July identified two cancer-causing chemicals in the vapor that the products release.

The US Food and Drug Administration (FDA) banned the sale of e-cigarettes to people under 18 earlier this year, and now require manufacturers to submit their ingredients for approval. The surgeon general’s report recommends stronger regulations, including a sales ban for people under the age of 21, higher taxes, and restrictions on marketing that targets young people.