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

The company's written statement came in response to a Japanese government report yesterday that two Nanos overheated in Tokyo, scorching nearby paper and a woven straw mat.

Apple said the flaw affects first-generation Nanos, sold between September 2005 and December 2006, in rare instances. The 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 has been working with Apple to investigate three instances 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, but Yoshitsune declined to name the battery supplier.

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 because they could overheat and ignite.

The two Tokyo incidents disclosed yesterday involved a Nano, model number MA099, that singed nearby paper in August, and a model MA005 that burned a traditional tatami mat in January. Both music players were twisted out of shape from the heat and became unusable, he said. In March, the Japanese ministry reported an incident of sparks shooting out of a Nano.