Juul Labs Inc. is considering opening retail stores in the United States, a source familiar with the matter said on Thursday, a move that would help the controversial company cash in on the booming popularity of its e-cigarettes.

The company has not made a final decision on the stores, which would only admit people aged 21 and above, the source added, asking not to be named as the matter is confidential.

Juul, along with other vaping device makers, has been under pressure from the U.S. Food and Drug Administration (FDA), which laid out plans in March to clamp down on the use of e-cigarettes among teens.

The company, in which Marlboro maker Altria Group has a 35% stake, has already pulled popular flavors such as mango and cucumber from retail store shelves and shut down its social media channels on Instagram and Facebook.

Altria is not involved in the company's plans, the source said.

The company plans to only sell tobacco, mint and menthol flavors in its stores. The first store would open in Texas, if the company were to go through with its plan, the source said, adding that Juul is eyeing cities with high smoking rates.

Juul, whose e-cigarettes resemble USB flash drives and work by vaporizing a nicotine-laced liquid, is also exploring opening stores in overseas markets including one in South Korea, according to the source.