Reports from a few iPhone 8 and iPhone 8 Plus buyers have suggested there could be an issue with the battery inside some of the devices swelling, causing the case of Apple’s new iPhone to split open and expose the smartphone’s internals.

Apple has now confirmed it is looking into it, although a spokeswoman declined to comment further when asked how many devices are affected.

From what we’ve heard the number of reports so far is very few.

Second Taiwan iPhone 8 buyer reports casing split open by swollen battery pic.twitter.com/lf6Tnp7wqc — Brightwire (@BrightwireInc) October 5, 2017

Yesterday CNET rounded up the handful of reports that have emerged — saying there are at least six different reports in at least five countries of the iPhone 8 splitting along its seams.

Today Reuters also noted a report in Chinese state media of an iPhone buyer claiming a newly purchased iPhone 8 Plus arrived cracked open on October 5, though apparently without any signs of scorching or an explosion.

Apple rival Samsung had big problems with smartphone batteries in its Galaxy Note 7 smartphone. In that instance some Note 7 batteries caught fire, and the problem was extensive enough that it led Samsung to recall all Note 7 handsets — at great expense.

In the case of the iPhone 8 the issue appears to be limited to batteries bloating/swelling, rather than catching fire — at least as reported so far.

Although the phone only went on sale on September 22 so it’s still early days for the device.

Apple did not release figures for the first weekend sales of the iPhone 8 and 8 Plus, as it has in the past with new iPhones, so it’s also not yet clear how many of these handsets are in the hands of buyers at this point.

Some analysts have suggested consumers may be holding off on upgrading their iPhone to buy the top-of-the-range iPhone X, which Apple also announced at the same time, but with a later release date.

Pre-sales for the iPhone X are due to begin on October 27, with the handset slated to ship on November 3.