Some 500 officers searched about 120 sites in Tokyo and neighboring Chiba and Kanagawa prefectures in unusually large raids to inspect possible violations of the Building Standards Law, news reports said.

"I'd like to see the investigation unveil all the facts," Construction Minister Kazuo Kitagawa said after a cabinet meeting.

"It's important to bring all the facts to light to prevent something similar from happening again," he said.

Japan, which experiences 20 percent of the world's major tremors, prides itself on strictly enforcing a quake-proof infrastructure.

But the scandal has steadily grown over the past month since architect Hidetsugu Aneha admitted he conspired with private inspectors and construction firms to falsify quake-resistance data.

At least 77 condominiums and hotels around Japan were found to have false earthquake data as of Monday, with some not strong enough even to withstand a moderate tremor, according to the construction ministry.

Television footage showed officers raiding the offices of Aneha and other firms including contractor Kimura Construction, which filed for bankruptcy protection after the scandal surfaced.

Aneha has been stripped of his architectural qualifications. Tetsuo Kutsukake, chairman of the National Public Safety Commission, said Tuesday that Japan was ready to press criminal charges if necessary.

Aneha said last week under questioning by parliament that he was under strenuous pressure to cut down the number of steel bars.

He said he specifically chose inspectors eHomes, whose offices were also raided Monday, because it was known for its allegedly sloppy work.

Japan has let the private sector inspect building designs in a liberalization measure in 1998.

Japan has announced an eight billion-yen (66 million-dollar) bailout plan for residents forced to move out of their condominiums due to the quake scandal.

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