Apple on Wednesday said external factors were the likely cause of fires in the batteries of its iPhone 6 model, Reuters reported. The company said the units it had analysed showed that they had suffered “external physical damage”, which led to the battery fires.

“We take every customer concern very seriously, including the limited number of reports of unexpected shutdown with iPhones,” Apple said in a statement, according to Forbes. “We also want to thank the agencies for forwarding concerns to us and their engagement with us.”

The statement came after a Chinese consumer protection body released a report on the matter. The Shanghai Consumer Council detailed the cases involving the battery fires, and also compared them to devices which were not part of a global iPhone 6 recall initiated by Apple on November 20.

Complaints regarding devices made by the United States-based company also went up sharply during the same time that South Korea’s Samsung was conducting a global recall of its Galaxy Note7 because of battery fires and explosions, the Council observed in its report. Analysts said Samsung’s recall had prompted Chinese consumers to question the safety standards followed by international brands.