In a rare move, the Defense Ministry plans to reprimand Adm. Tomohisa Takei, chief of staff of the Maritime Self-Defense Force, for exerting inappropriate pressure during the selection process for a next-generation helicopter to replace the UH-60J, government sources said.

Top-ranking officers are rarely reprimanded, but the decision was prompted by a probe conducted by a special unit under the defense minister, and based on whistle-blower information that alleged the MSDF's preferred choice for the next-generation chopper was improperly changed, the sources said Thursday.

The incident will delay the MSDF's plan to procure nine multipurpose helicopters by the end of March 2019. The choppers are being bought to counter China's activities in the East China Sea and for other purposes.