TOKYO (AP) -- The mammoth earthquake that ravaged northern Japan this week did more than take lives and trigger radioactive leaks. It nailed some of the most important industries under girding growth in the world's second-biggest economy.

As of Thursday, Toyota, Nissan, Honda, Mitsubishi, Mazda and Fuji Heavy Industries, the maker of Subaru vehicles, halted production at some factories because a key parts supplier, Riken Corp., was damaged by the temblor. The Nikkei business newspaper reported that about 70 percent of Japan's domestic auto production had been interrupted because of the hitch. Meanwhile, fears of an electricity shortage in the nation's capital swelled after the world's biggest nuclear power plant was shut down indefinitely because of safety concerns. Tokyo Electric Power Co., Japan's largest utility, was scrambling to ramp up conventional power output after closing the quake-damaged Kashiwazaka-Karima facility in Niigata prefecture, in north-central Japan. ""We will work to the utmost to avoid damage to the economy,"" Chief Cabinet Secretary Yasuhisa Shiozaki said Thursday. ""For the factories that suspended operations, the related ministries are striving hard for their early resumption."" Monday's quake, which killed 10 people and caused a slew of problems at TEPCO's nuclear plant, including a fire and leaks of radioactive material into the ocean, has wreaked havoc companies with factories in the region and created a logistics nightmare with damaged roads. Autos and electric power are key to Japan's export-oriented economy, which is staging a healthy recovery from more than a decade of doldrums. While any lasting impact on overall growth will likely be limited, even a small blip would be unwelcome. The auto companies' troubles stemmed largely from damage at a factory run by Riken, a supplier of key transmission and engine parts. Toyota Motor Corp., Nissan Motor Co., Mitsubishi Motors Corp. and Fuji Heavy Industries Ltd. announced late Wednesday they would temporarily halt some of their lines for lack of components as Riken repairs its facilities. Honda Motor Co., Mazda Motor Corp. and truckmakers Mitsubishi Fuso and Hino joined their ranks on Thursday. ""It's usually deafening with all the equipment running. But we've had to shut everything down,"" Riken spokesman Takashi Fujii said while giving a tour of the damaged plant to reporters. ""The equipment is very sensitive and it needs to be on a level surface. But most of it was tilted in the quake or completely moved out of position."" Still, analysts said the delay — if short enough — probably wouldn't affect domestic or overseas deliveries for big players such as Toyota, which has enough inventory to cover a few days of lost output. Elsewhere in the quake zone, Fuji Xerox Co. halted a damaged printer plant. For Sanyo Electric Co., Monday's rumble was edgy close call. Sanyo briefly closed the plant again after Monday's quake but reopened it after determining there was no damage. Any financial impact this time would be minimal, it said in a statement