Japanese authorities reported Tuesday the first case of an Apple laptop catching fire in Japan and ordered the U.S. company to investigate the trouble involving the faulty Sony batteries and report back within a week.

A laptop made by Apple Computer overheated and caught fire in April, the Ministry of Economy, Trade and Industry said. The user sustained minor burns after the the iBook G4 computer caught fire, according to Apple spokeswoman Michiko Matsumoto, who confirmed the case.

Last week, Apple told its customers to return 1.8 million iBook G4 and PowerBook G4 batteries worldwide that could cause their laptops to overheat and catch fire _ just 10 days after Dell Inc. recalled 4.1 million faulty laptop batteries for the same reason. It was the largest recall involving electronics in the history of the U.S. Consumer Product Safety Commission.

In both cases, the problematic lithium-ion batteries were made by Sony Energy Devices , a subsidiary of Sony based in Japan.

Apple has received nine reports in the United States of the lithium-ion batteries battery packs overheating, including two consumers who received minor burns after handling overheated computers. Apple has also received reports of minor property damage, but no serious injuries have been reported.

Japan's trade ministry ordered Apple's Japan branch to report on its findings and measures to prevent future troubles by Sept. 5 or it could face a fine of up to 300,000 yen ($2,570) under Japan's consumer safety laws.

Sony and Dell also have been ordered to report on their findings after the recall was announced by the ministry.

Last week, ministry officials reported that batteries in Dell laptops imported to Japan caught fire in at least two separate instances in October and June. No one was injured in those incidents, but the fires destroyed the machines.

Battery packs contain cells of rolled up metal strips. Sony has said that during production, crimping the rolls left tiny shards of metal loose in the cells, and some of those shards can cause batteries to short-circuit, or in extreme cases, catch fire.

Apple's Matsumoto declined to say the number of batteries the recall involves in Japan and how many have been recalled. A call to an Apple corporate spokesman in Cupertino, Calif., was not immediately returned early Tuesday.

The trade ministry has also instructed other Japanese electronic makers to check the safety of their laptop batteries.