Ichiro Ozawa refused Tuesday to submit to questioning over his alleged accounting irregularities, his lawyers said, raising the likelihood that the former head of the Democratic Party of Japan will face mandatory indictment possibly as soon as this week.

Ozawa's defense team conveyed his refusal to the court-appointed lawyers acting as prosecutors in the case.

Because the written notice didn't give a reason for the refusal, the acting prosecutors concluded there is no room left for negotiations, sources said.