SEOUL/BEIJING (Reuters) - A battery supplier to Samsung Electronics Co Ltd (>> Samsung Electronics Co Ltd) said on Monday a Galaxy Note 7 smartphone that reportedly caught fire on its own in China appears to have been caused by an external factor.

Amperex Technology Limited (ATL) said it conducted a joint investigation with Samsung on the phone in question and determined the incident was not directly related to the batteries produced by ATL.

A Samsung spokeswoman referred to ATL's statement and declined to comment further.

(Reporting by Se Young Lee and Paul Carsten; Editing by Christopher Cushing)

Stocks treated in this article : TDK Corp, Samsung Electronics Co Ltd