Prosecutors raided engineering firm JGC Corp., the consultancy Nippon Koei Co. and other locations Wednesday in connection with alleged bid-manipulation over the construction of a Japanese-funded building on Kunashiri, a Russian-held island claimed by Japan.

According to investigative sources, JGC approached Akira Miyano, a senior secretary of lawmaker Muneo Suzuki, to seek his help and brokered a deal for the project with two construction companies in Hokkaido, Suzuki's constituency.

The sources alleged that Miyano interfered in the July 1999 bidding for the project by arranging for a local joint venture to win the contract.