Two brothers of disgraced Seibu group patriarch Yoshiaki Tsutsumi proposed Monday buying Seibu Railway Co., casting a pall over a group reorganization plan drawn up by the firm's management.

Under the proposal, the brothers -- Yuji and Seiji Tsutsumi -- said they would pay up to 560 billion, yen or 1,300 yen per share, to acquire the entire stake in the railway through a tender offer bid.

The announcement came only a few weeks after the current Seibu Railway management agreed with U.S. investment fund Cerberus Group, Nikko Principal Investments Japan Ltd. and others for a capital injection of up to 160 billion yen as part of the turnaround plan for the scandal-tainted conglomerate.