Factory lines across a swathe of central Japan remained suspended Tuesday in the wake of a powerful earthquake as aftershocks and power and communication blackouts hampered efforts to assess the damage. But large firms expressed hope that the damage wrought by Monday`s tremor -- which measured 6.8 on the Richter scale -- would be less severe than that caused by a quake of a similar magnitude that rocked the same region in 2004. Japanese share prices suffered modest losses, led lower by insurers as investors waited for a clearer indication of the financial costs. The Tokyo Stock Exchange`s benchmark Nikkei-225 index of leading shares was down 27.64 points or 0.15 percent at 18,211.31 by mid-afternoon. Among companies affected by the quake northwest of Tokyo, auto parts maker Riken Corp. said it was unsure when it would resume operations because aftershocks were continuing to rattle the region. It said one of its warehouses was partly damaged, machinery was bumped around and some equipment and stockpiles toppled over following the quake, which killed at least nine people and injured more than 1,000. Tokyo Electric Power Co. Inc. (TEPCO) was forced to shut down its Kashiwazaki-Kariwa nuclear plant, the largest in the world, and reported that a small amount of radioactive water leaked into the sea following the quake. Electronics maker Sanyo Electric Co., which suffered major damage at one of its semiconductor plants during the 2004 quake, said that this time the factory appeared to have escaped major damage. "Employees were evacuated immediately although no one was injured. There is no damage to buildings," said Sanyo spokesman Akihiko Oiwa. He said production remained suspended as aftershocks rattled the plant but the company expected to resume operations there later Tuesday. Fuji Xerox Co., which has a plant in the affected area, said it was still unsure how badly its facilities were affected because of disruption to power and telecommunications. "We are unable to assess the extent of the damage or the situation. Until we reinstall communication, we can`t give any more details," said company spokeswoman Hiroko Hattori. Bourbon, a confectionery manufacturer headquartered in badly hit Kashiwazaki, said that its facilities had been only lightly damaged, while glass maker Okamoto Glass said it also appeared to have escaped serious damage.