A similar incident reportedly happened in Britain, where a person claims an iPod Touch exploded and flew into the air.
The Consumer Products Safety Commission has records of 15 reported burn and fire-related incidents involving iPods last year. The Japanese government warned of fire risks from the iPod Nano last year.
Apple is cooperating with investigations of the alleged incidents, which it describes as "isolated." An Apple spokesperson says the company is aware of the reports, but it won't comment until it receives more information.