Apple said the flaw affected first-generation Nanos, sold between September 2005 and December 2006, in very rare instances. The company’s statement added that “There have been no reports of serious injuries or property damage, and no reports of incidents for any other iPod Nano model.”

Japan’s government has been working with Apple to investigate three separate cases of iPods that overheated while being recharged, according to Ministry of Economy, Trade and Industry official Hiroyuki Yoshitsune. A defect in the lithium-ion battery was suspected in all three cases.

Millions of lithium-ion laptop batteries made by Sony for Apple, Dell Inc., Lenovo Inc. and other PC makers were recalled in 2006 and 2007 after it was discovered that they could overheat and ignite.

Apple did not immediately return a call seeking the name of the company that made the iPod batteries in question. Yoshitsune declined to name the supplier.

No one was injured during the two Tokyo incidents disclosed Tuesday. Yoshitsune said the cases involved an iPod Nano, model number MA099, which singed nearby paper in August, and model MA005, which burned a traditional Japanese tatami mat in January. Both music players were twisted out of shape from the heat and became unusable, he said.

The latest problem follows a similar report from the Japanese ministry in March about sparks shooting out of an iPod Nano.

Apple’s iPod players are extremely popular in Japan and coveted as fashion items, even though Japanese manufacturers produce a host of iPod rivals.

(SEATTLE) — Apple Inc. said Tuesday that batteries from a single supplier are to blame for the meltdown of some models of its tiny iPod Nano digital music player.