Fukushima Gov. Eisaku Sato tendered his resignation to the prefectural assembly Wednesday on the heels of the arrest of his brother and a former senior prefectural official over alleged bid-rigging for a public works contract.

Sato said, "I decided to put an end to my 18-year-career (as governor) to take moral responsibility and to restore public trust in the prefectural administration as soon as possible."

The governor denied any personal involvement in the scandal.

After serving in the House of Councilors, Sato won the gubernatorial seat in 1988 and is now serving his fifth consecutive term.

Sato drew public attention for some of the steps he took in running the prefectural government, including expressing support for municipalities that did not merge with each other despite the central government's urging.

Sato's brother, Yuji, 63, was arrested Monday by a special squad of the Tokyo District Public Prosecutor's Office on suspicion of prearranging contractors' bids.

Since Sept. 6, Sato's brother has been questioned on and off by law-enforcement officials. Sato had said he "believes his brother," but after the arrest, he said, "I feel sorry for bringing anxiety to citizens in the prefecture."

Others bid-rigging arrests include a former head of the local government's civil engineering division, and a company president and key supporter of the governor.

In July, prosecutors raided Sato's brother's home and his company in relation to a tax evasion case involving the engineering firm Mizutani Kensetsu Co. based in Mie Prefecture.