Apple is recalling more than one million laptop computer batteries fearing they could burst into flames, the US Consumer Product Safety Commission said. The recall centered on lithium-ion batteries made by Japan-based Sony and sold with some iBook G4 and PowerBook G4 computers, according to the commission.

"We discovered that some Sony batteries in previous models of power PC-based iBooks and PowerBooks do not meet Apple's standards for safety and performance," Apple spokesman Steve Dowling said in an interview with AFP.

"Our number-one priority is to recall and replace the affected batteries free of charge."

The recall did not involve any of Apple's new laptops powered by Intel computer chips, according to Dowling.

The Apple announcement came after Dell Computer Corporation recalled some 4.1 million laptop batteries with Sony-made cells, also as a fire hazard.

Japan's industry ministry ordered Sony and Dell on Thursday to investigate reports that some laptop batteries made by the Japanese electronics giant have overheated and caught fire.

At least two such incidents have been reported in Japan since October of last year, according to the ministry.

The Japanese electronics giant said in a statement Friday that the overall cost of supporting those recalls would amount to some 20-30 billion yen (171-257 million dollars). No further recalls were expected, it added.

Sony has said the problems of overheating and fires did not stem from a problem with the original design of the batteries but were tied to a number of factors linked to the integration and configuration with the Dell computers.

Apple has received nine reports of batteries overheating, the US Consumer Product Safety Commission said. In two cases, people suffered minor burns, and in others, property was damaged, the commission reported.

It estimated that 1.1 million Apple laptop batteries would be recalled in the United States and another 700,000 in other countries.

The batteries were sold with laptops and separately from October 2003 until this month, according to the commission.

Apple posted details of the recall at its website and did not expect to incur "a material financial impact."

Dell arranged its Sony-made battery recall less than two weeks ago in cooperation with the Consumer Product commission. Texas-based Dell said it had logged six "incidents" involving the laptop batteries.

Batteries designated for recall were sold with Dell Latitude and Inspiron notebook computers, as well as the Precision model mobile workstations from April 1, 2004 through July 18, 2006, the company said in a release.

The batteries were sometimes sold separately during service calls, according to Dell.

Dell Batteries targeted for recall are imprinted with the Dell company name and either "Made in Japan," "Made in China," or "Battery Cell Made in Japan Assembled in China," the company said.

Apple urged owners of the affected iBook and PowerBook laptops to stop using the batteries immediately and order a free replacement through the company.