Updated

The Japanese electronics maker Toshiba Corp. said Friday that it is recalling 830,000 batteries made by Sony (SNE) for its laptop computers while personal computer maker Dell Inc. (DELL) expanded its recall of Sony battery packs by 100,000.

The batteries can short-circuit and have been blamed for causing some computers to catch fire.

The latest announcements bring the tally of recalled Sony batteries to about 7 million worldwide, and are a major embarrassment for the Japanese electronics and entertainment powerhouse.

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The recall comes as Sony Corp. is in the midst of a major overhaul of its operations, closing plants, shutting divisions and trimming jobs.

Sony said earlier Friday it had asked manufacturers using its problem batteries to carry out a recall.

It has said the batteries could catch fire in rare cases when microscopic metal particles came into contact with other parts of the battery cell, leading to a short circuit.

Typically a battery pack will power off when there is a short circuit but on occasion the battery would catch fire instead.

Fujitsu Ltd., another major Japanese electronics company, will be making a decision soon about its laptops using Sony lithium-ion batteries, spokesman Masao Sakamoto said Friday.

The Toshiba recall involves Dynabook, Qosmio, Satellite Portege and Tecra models, but regional breakdowns and dates of manufacturing weren't immediately available, said Toshiba spokesman Keisuke Omori.

Omori said Toshiba's recall was in response to Sony's request, and Toshiba had not found any cases in which the laptops were at risk of catching fire.

"But we wanted to assure and satisfy our customers," he said.

Dell, the world's largest personal computer maker, said Friday that it is increasing the recall of Sony battery packs used in its systems to 4.2 million units from 4.1 million units. It already was the largest electronics-related recall in U.S. history.

Based in Round Rock, Texas, Dell said that the increase in the recall was made due to additional information received about the affected battery packs containing cells manufactured by Sony.

Dell and the Consumer Product Safety Commission announced the initial recall on Aug. 15, blaming Sony battery cells. Dell began shipping replacement batteries on Aug. 15.

On Friday, Dell said customers should recheck their batteries if they have not ordered or received a replacement battery.

On Thursday, IBM Corp. (IBM) and Lenovo Group, the world's third-largest computer maker, said they were seeking the recall of 526,000 rechargeable, lithium-ion Sony batteries purchased with ThinkPad computers after one of them caught fire at Los Angeles International Airport this month.

In August, Apple Computer Inc. (AAPL) recalled 1.8 million batteries worldwide, warning they could catch fire.

Last week, Toshiba said it was recalling 340,000 laptop batteries, also made by Sony, but that was for a problem that caused the laptops to run out of power.