Three employees at one of Marubeni Corp.'s grain trading units in China have been detained by authorities, the trading house said Thursday, a move sources said was prompted by allegations it evaded taxes on soybean imports.

The employees worked at a Chinese unit of Marubeni's Columbia Grain Inc., a spokesman at the trading company said. He added he did not know why they had been detained. He also said he did not know the nationalities of the employees.

The detentions may signal further complications in strained relations between Japan and China. Mitsui O.S.K. Lines Ltd. has paid about ¥4 billion to Chinese claimants, stemming from a wartime claim after the seizure of one of its ships by a court in Shanghai, according to media reports.