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.

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

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.