A teenager in Arizona, US says her iPhone 7 Plus (not pictured) “blew up” while charging. Picture: Sean Gallup/Getty Images

The teenager, Brianna Olivas, posted a video on Twitter this week showing her showing her rose-gold iPhone 7 Plus with a melted case smouldering on a bathroom counter.

She said the phone began spewing smoke while it was charging.

“So my iPhone 7 plus blew up this morning... was not even using it, literally no explanation for this,” she wrote along with the video.

Apple said they were investigating the incident.

“We are in touch with the customer and looking into it,” an Apple representative told Mashable, which first reported the news.

For now, there’s no evidence that the charred remains of this particular iPhone 7 are anything but an isolated incident, although in October Australian surf instructor Mat Jones reported a similar incident with the smartphone.

Apple did not respond to a request for further information on Friday, Reuters reported.

Last year, Samsung took a major financial hit after its high-end Galaxy Note 7 smartphone turned out to be at risk for catching fire or even exploding because of a battery design flaw.

The company issued a recall but its replacement units had the same issue.

Samsung was forced to kill off the device, which the company said would result in losses of more than $6.5 billion.