Apple said Monday it would investigate claims that a Chinese woman was killed by an electric shock she received when answering a call while the device was charging.
The claim quickly drew attention after a woman in the western region of Xinjiang wrote about the death of her 23-year-old sister Ma Ailun on China's popular microblog service Sina Weibo.
"We will fully investigate and cooperate with authorities in this matter," said Apple's Beijing-based spokeswoman Carolyn Wu, offering condolences to the family.
The state news agency Xinhua said on Sunday that local police had confirmed Ma died of electrocution but "have yet to verify if her phone was involved".
Ma's sister warned others not to use their phones while they were charging and asked Apple to provide an explanation, saying on Weibo on Saturday: "What a shame, to pass away like this."
Weibo users responded with concern about the potential danger but also questioned if the claim was real.
"If the accidents are real, let's be more careful when using our mobiles," one person said, but added: "Is someone trying to smear Apple?"
China is Apple's second largest market but the company recently came under criticism from state media in April for alleged "arrogance" and double standards, prompting an apology from chief executive Tim Cook.
The People's Daily, a mouthpiece of the ruling Communist Party, slammed the firm for five days in a row, urging consumers to "strike away Apple's unparalleled arrogance".
Chinese consumers had to pay about $80 for new back covers for their devices, even though they were free in other markets, local media reported at the time.
In a Chinese-language letter, Cook said "we sincerely apologize for any concerns or misunderstanding".
Apple had "many things we have to learn" about operating in the country, he added.
AFP contributed to this report.