Three Apple iPod Nano music players have overheated and two scorched nearby paper and a straw woven mat in Tokyo, Japan.
A Japanese government official said they are investigating a possible battery defect in the popular iPod Nano.
No one was injured, and there was no further damage, said Ministry of Economy, Trade and Industry official Hiroyuki Yoshitsune.
The latest problem follows a similar ministry report in March about sparks shooting out of an iPod Nano, he said.
The government has been working with Apple to investigate the cause, and a defect in the lithium-ion battery is suspected in all three cases, he said. The iPods began to overheat while they were being recharged, he said.
He declined to disclose the manufacturers of the batteries, and said it was unclear whether the same battery was being packaged in the product, which is sold all over the world.
Apple Japan did not have immediate comment.
Yoshitsune said the two latest cases involved an iPod Nano, which singed nearby paper in August, and another which burned a Japanese traditional "tatami" mat, in January. Both players were twisted out of shape from the heat and became unusable, he said.
The government has instructed Apple Japan to find out the cause of the problems and report back to the government.
