He went on to say that only batteries that are overheating are eligible for free replacement and that the iPod Nano batteries are not being recalled.
The Apple spokesman said, "We are still investigating the cause of the glitch, but we've identified one particular supplier of the batteries."
On Tuesday, the Ministry of Economy, Trade and Industry warned users that Apple's iPods could catch fire.
It said it had notified Apple of 17 battery overheating incidents, including two recent reports of minor fires in Tokyo and two previous cases in which users received minor burns.
The ministry said that about 1.81 million iPod Nanos sold in Japan between September 2005 and September 2006 might be potential fire risks.
L'Inq AFP