WASHINGTON (AP) — U.S. health officials will begin cracking down on most flavored e-cigarettes that are popular with underage teenagers, but their plan includes major exceptions that benefit vaping manufacturers, retailers and adults who use the nicotine-delivery devices.

The Trump administration announced Thursday that it will prohibit fruit, candy, mint and dessert flavors from small, cartridge-based e-cigarettes favored by high school and middle school students. But menthol and tobacco-flavored e-cigarettes will be allowed to remain on the market.

The targeted flavor ban will also entirely...