Apple has acknowledged that a number of iPhone 5s devices are suffering from battery problems.
"We recently discovered a manufacturing issue affecting a very limited number of iPhone 5s devices that could cause the battery to take longer to charge or result in reduced battery life," an Apple spokeswoman told the New York Times.
Any users seeing malfunctioning batteries will be offered new devices. "We are reaching out to customers with affected phones and will provide them with a replacement phone," the spokeswoman said.
According to the paper several thousand units, out of the millions of 5s handsets sold so far, are thought to be affected. Apple said it sold nine million of its newly-launched 5s and 5c devices in the three days following launch, but did not detail how many of each device were bought.
ZDNet has asked Apple for comment and will update the story if any is forthcoming.